Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| structure of the 40s ribosomal subunit of plasmodium falciparum by homology and de novo modeling. | generation of three dimensional structures of macromolecules using in silico structural modeling technologies such as homology and de novo modeling has improved dramatically and increased the speed by which tertiary structures of organisms can be generated. this is especially the case if a homologous crystal structure is already available. high-resolution structures can be rapidly created using only their sequence information as input, a process that has the potential to increase the speed of sc ... | 2016 | 28119814 |
| structure of the 40s ribosomal subunit of plasmodium falciparum by homology and de novo modeling. | generation of three dimensional structures of macromolecules using in silico structural modeling technologies such as homology and de novo modeling has improved dramatically and increased the speed by which tertiary structures of organisms can be generated. this is especially the case if a homologous crystal structure is already available. high-resolution structures can be rapidly created using only their sequence information as input, a process that has the potential to increase the speed of sc ... | 2016 | 28119814 |
| metagenomic analysis of hot springs in central india reveals hydrocarbon degrading thermophiles and pathways essential for survival in extreme environments. | extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. india harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. the aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central india namel ... | 2016 | 28105025 |
| metagenomic analysis of hot springs in central india reveals hydrocarbon degrading thermophiles and pathways essential for survival in extreme environments. | extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. india harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. the aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central india namel ... | 2016 | 28105025 |
| amylose recognition and ring-size determination of amylomaltase. | starch is a major carbon and energy source throughout all kingdoms of life. it consists of two carbohydrate polymers, branched amylopectin and linear amylose, which are sparingly soluble in water. hence, the enzymatic breakdown by glycoside hydrolases (ghs) is of great biological and societal importance. amylomaltases (ams) are ghs specialized in the hydrolysis of α-1,4-linked sugar chains such as amylose. they are able to catalyze an intramolecular transglycosylation of a bound sugar chain yiel ... | 2017 | 28097217 |
| an ambiguity principle for assigning protein structural domains. | ambiguity is the quality of being open to several interpretations. for an image, it arises when the contained elements can be delimited in two or more distinct ways, which may cause confusion. we postulate that it also applies to the analysis of protein three-dimensional structure, which consists in dividing the molecule into subunits called domains. because different definitions of what constitutes a domain can be used to partition a given structure, the same protein may have different but equa ... | 2017 | 28097215 |
| redox signaling through dna. | biological electron transfer reactions between metal cofactors are critical to many essential processes within the cell. duplex dna is, moreover, capable of mediating the transport of charge through its π-stacked nitrogenous bases. increasingly, [4fe4s] clusters, generally redox-active cofactors, have been found to be associated with enzymes involved in dna processing. dna-binding enzymes containing [4fe4s] clusters can thus utilize dna charge transport (dna ct) for redox signaling to coordinate ... | 2016 | 28090121 |
| integrating mass spectrometry with md simulations reveals the role of lipids in na(+)/h(+) antiporters. | na(+)/h(+) antiporters are found in all kingdoms of life and exhibit catalysis rates that are among the fastest of all known secondary-active transporters. here we combine ion mobility mass spectrometry and molecular dynamics simulations to study the conformational stability and lipid-binding properties of the na(+)/h(+) exchanger napa from thermus thermophilus and compare this to the prototypical antiporter nhaa from escherichia coli and the human homologue nha2. we find that napa and nha2, but ... | 2017 | 28071645 |
| activation of respiratory complex i from escherichia coli studied by fluorescent probes. | respiratory complex i from e. coli may exist in two interconverting forms: resting (r) and active (a). the r/a transition of purified, solubilized complex i occurring upon turnover was studied employing two different fluorescent probes, annine 6+, and ndb-acetogenin. nadh-induced fluorescent changes of both dyes bound to solubilized complex i from e. coli were characterized as a function of the protein:dye ratio, temperature, ubiquinone redox state and the enzyme activity. analysis of this data ... | 2017 | 28070565 |
| editorial: filamentous bacteriophage in bio/nano/technology, bacterial pathogenesis and ecology. | 2016 | 28066406 | |
| homology-based modeling of universal stress protein from listeria innocua up-regulated under acid stress conditions. | an universal stress protein (usp) expressed under acid stress condition by listeria innocua atcc 33090 was investigated. the usp was up-regulated not only in the stationary phase but also during the exponential growth phase. the three dimensional (3d) structure of usp was predicted using a combined proteomic and bioinformatics approach. phylogenetic analysis showed that the usp from listeria detected in our study was distant from the usps of other bacteria (such as pseudomonas spp., escherichia ... | 2016 | 28066336 |
| exploring conformational equilibria of a heterodimeric abc transporter. | abc exporters pump substrates across the membrane by coupling atp-driven movements of nucleotide binding domains (nbds) to the transmembrane domains (tmds), which switch between inward- and outward-facing (if, of) orientations. deer measurements on the heterodimeric abc exporter tm287/288 from thermotoga maritima, which contains a non-canonical atp binding site, revealed that in the presence of nucleotides the transporter exists in an if/of equilibrium. while atp binding was sufficient to partia ... | 2017 | 28051765 |
| thermophilic bacteria are potential sources of novel rieske non-heme iron oxygenases. | rieske non-heme iron oxygenases, which have a rieske-type [2fe-2s] cluster and a non-heme catalytic iron center, are an important family of oxidoreductases involved mainly in regio- and stereoselective transformation of a wide array of aromatic hydrocarbons. though present in all domains of life, the most widely studied rieske non-heme iron oxygenases are found in mesophilic bacteria. the present study explores the potential for isolating novel rieske non-heme iron oxygenases from thermophilic s ... | 2017 | 28050858 |
| a cascade of thermophilic enzymes as an approach to the synthesis of modified nucleotides. | we propose a new approach for the synthesis of biologically important nucleotides which includes a multi-enzymatic cascade conversion of d-pentoses into purine nucleotides. the approach exploits nucleic acid exchange enzymes from thermophilic microorganisms: ribokinase, phosphoribosylpyrophosphate synthetase, and adenine phosphoribosyltransferase. we cloned the ribokinase gene from thermus sp. 2.9, as well as two different genes of phosphoribosylpyrophosphate synthetase (prpp-synthetase) and the ... | 2016 | 28050269 |
| crispr-mediated epigenome editing. | mounting evidence has called into question our understanding of the role that the central dogma of molecular biology plays in human pathology. the conventional view that elucidating the mechanisms for translating genes into proteins can account for a panoply of diseases has proven incomplete. landmark studies point to epigenetics as a missing piece of the puzzle. however, technological limitations have hindered the study of specific roles for histone post-translational modifications, dna modific ... | 2016 | 28018139 |
| dynamic complexes in the chaperonin-mediated protein folding cycle. | the groel-groes chaperonin system is probably one of the most studied chaperone systems at the level of the molecular mechanism. since the first reports of a bacterial gene involved in phage morphogenesis in 1972, these proteins have stimulated intensive research for over 40 years. during this time, detailed structural and functional studies have yielded constantly evolving concepts of the chaperonin mechanism of action. despite of almost three decades of research on this oligomeric protein, cer ... | 2016 | 28008398 |
| in situ spectroscopy reveals that microorganisms in different phyla use different electron transfer biomolecules to respire aerobically on soluble iron. | absorbance spectra were collected on 12 different live microorganisms, representing six phyla, as they respired aerobically on soluble iron at ph 1.5. a novel integrating cavity absorption meter was employed that permitted accurate absorbance measurements in turbid suspensions that scattered light. illumination of each microorganism yielded a characteristic spectrum of electrochemically reduced colored prosthetic groups. a total of six different patterns of reduced-minus-oxidized difference spec ... | 2016 | 28008327 |
| coupled atpase-adenylate kinase activity in abc transporters. | atp-binding cassette (abc) transporters, a superfamily of integral membrane proteins, catalyse the translocation of substrates across the cellular membrane by atp hydrolysis. here we demonstrate by nucleotide turnover and binding studies based on (31)p solid-state nmr spectroscopy that the abc exporter and lipid a flippase msba can couple atp hydrolysis to an adenylate kinase activity, where adp is converted into amp and atp. single-point mutations reveal that both atpase and adenylate kinase me ... | 2016 | 28004795 |
| cryo-em structures of the autoinhibited e. coli atp synthase in three rotational states. | a molecular model that provides a framework for interpreting the wealth of functional information obtained on the e. coli f-atp synthase has been generated using cryo-electron microscopy. three different states that relate to rotation of the enzyme were observed, with the central stalk's ε subunit in an extended autoinhibitory conformation in all three states. the fo motor comprises of seven transmembrane helices and a decameric c-ring and invaginations on either side of the membrane indicate th ... | 2016 | 28001127 |
| mapping the membrane proteome of anaerobic gut fungi identifies a wealth of carbohydrate binding proteins and transporters. | engineered cell factories that convert biomass into value-added compounds are emerging as a timely alternative to petroleum-based industries. although often overlooked, integral membrane proteins such as solute transporters are pivotal for engineering efficient microbial chassis. anaerobic gut fungi, adapted to degrade raw plant biomass in the intestines of herbivores, are a potential source of valuable transporters for biotechnology, yet very little is known about the membrane constituents of t ... | 2016 | 27998268 |
| comparison of lipases and glycoside hydrolases as catalysts in synthesis reactions. | lipases and glycoside hydrolases have large similarities concerning reaction mechanisms. acyl-enzyme intermediates are formed during lipase-catalyzed reactions and in an analogous way, retaining glycoside hydrolases form glycosyl-enzyme intermediates during catalysis. in both cases, the covalent enzyme intermediates can react with water or other nucleophiles containing hydroxyl groups. simple alcohols are accepted as nucleophiles by both types of enzymes. lipases are used very successfully in sy ... | 2016 | 27995311 |
| comparison of lipases and glycoside hydrolases as catalysts in synthesis reactions. | lipases and glycoside hydrolases have large similarities concerning reaction mechanisms. acyl-enzyme intermediates are formed during lipase-catalyzed reactions and in an analogous way, retaining glycoside hydrolases form glycosyl-enzyme intermediates during catalysis. in both cases, the covalent enzyme intermediates can react with water or other nucleophiles containing hydroxyl groups. simple alcohols are accepted as nucleophiles by both types of enzymes. lipases are used very successfully in sy ... | 2016 | 27995311 |
| conservation of coevolving protein interfaces bridges prokaryote-eukaryote homologies in the twilight zone. | protein-protein interactions are fundamental for the proper functioning of the cell. as a result, protein interaction surfaces are subject to strong evolutionary constraints. recent developments have shown that residue coevolution provides accurate predictions of heterodimeric protein interfaces from sequence information. so far these approaches have been limited to the analysis of families of prokaryotic complexes for which large multiple sequence alignments of homologous sequences can be compi ... | 2016 | 27965389 |
| systematic analysis of the lysine acetylome in fusarium graminearum. | lysine acetylation in proteins is a ubiquitous and conserved post-translational modification, playing a critical regulatory role in almost every aspect of living cells. although known for many years, its function remains elusive in fusarium graminearum, one of the most important necrotrophic plant pathogens with huge economic impact. | 2016 | 27964708 |
| the mechanism of a formaldehyde-sensing transcriptional regulator. | most organisms are exposed to the genotoxic chemical formaldehyde, either from endogenous or environmental sources. therefore, biology has evolved systems to perceive and detoxify formaldehyde. the frmra(b) operon that is present in many bacteria represents one such system. the frmr protein is a transcriptional repressor that is specifically inactivated in the presence of formaldehyde, permitting expression of the formaldehyde detoxification machinery (frma and frmb, when the latter is present). ... | 2016 | 27934966 |
| computing and applying atomic regulons to understand gene expression and regulation. | understanding gene function and regulation is essential for the interpretation, prediction, and ultimate design of cell responses to changes in the environment. an important step toward meeting the challenge of understanding gene function and regulation is the identification of sets of genes that are always co-expressed. these gene sets, atomic regulons (ars), represent fundamental units of function within a cell and could be used to associate genes of unknown function with cellular processes an ... | 2016 | 27933038 |
| pb(2+) effects on growth, lipids, and protein and dna profiles of the thermophilic bacterium thermus thermophilus. | extremophiles are organisms able to thrive in extreme environmental conditions and some of them show the ability to survive high doses of heavy metals thanks to defensive mechanisms provided by primary and secondary metabolic products, i.e., extremolytes, lipids, and extremozymes. this is why there is a growing scientific and industrial interest in the use of thermophilic bacteria in a host of tasks, from the environmental detoxification of heavy metal to industrial activities, such as bio-machi ... | 2016 | 27929414 |
| molecular mechanisms of substrate specificities of uridinecytidine kinase. | a uridine-cytidine kinase (uck) catalyzes the phosphorylation of uridine (urd) and cytidine (cyd) and plays a significant role in the pyrimidine-nucleotide salvage pathway. unlike ordinary ones, uck from thermus thermophilus hb8 (ttck) loses catalytic activity on urd due to lack of a substrate binding ability and possesses an unusual amino acid, i.e. tyrosine 93 (tyr93) at the binding site, whereas histidine (his) is located in the other ucks. mutagenesis experiments revealed that a replacement ... | 2016 | 27924260 |
| a decade of biochemical and structural studies of the dna repair machinery of deinococcus radiodurans: major findings, functional and mechanistic insight and challenges. | the deinococcus radiodurans bacterium is extremely resistant to ionising radiation and desiccation and can withstand a 200-fold higher radiation dose than most other bacteria with no loss of viability. the mechanisms behind this extreme resistance are not fully understood, but it is clear that several factors contribute to this phenotype. efficient scavenging of reactive oxygen species and repair of damaged dna are two of these. in this review, we summarise the results from a decade of structura ... | 2016 | 27924191 |
| first resistance mechanisms characterization in glyphosate-resistant leptochloa virgata. | leptochloa virgata (l.) p. beauv. is an annual weed common in citrus groves in the states of puebla and veracruz, mexico limiting their production. since 2010, several l. virgata populations were identified as being resistant to glyphosate, but studies of their resistance mechanisms developed by this species have been conducted. in this work, three glyphosate-resistant populations (r8, r14, and r15) collected in citrus orchards from mexico, were used to study their resistance mechanisms comparin ... | 2016 | 27917189 |
| improved in-cell structure determination of proteins at near-physiological concentration. | investigating three-dimensional (3d) structures of proteins in living cells by in-cell nuclear magnetic resonance (nmr) spectroscopy opens an avenue towards understanding the structural basis of their functions and physical properties under physiological conditions inside cells. in-cell nmr provides data at atomic resolution non-invasively, and has been used to detect protein-protein interactions, thermodynamics of protein stability, the behavior of intrinsically disordered proteins, etc. in cel ... | 2016 | 27910948 |
| identification of a highly conserved hypothetical protein ton_0340 as a probable manganese-dependent phosphatase. | a hypothetical protein ton_0340 of a thermococcus species is a protein conserved in a variety of organisms including human. herein, we present four different crystal structures of ton_0340, leading to the identification of an active-site cavity harboring a metal-binding site composed of six invariant aspartate and glutamate residues that coordinate one to three metal ions. biochemical and mutational analyses involving many phosphorous compounds show that ton_0340 is a mn2+-dependent phosphatase. ... | 2016 | 27907125 |
| structure of the 70s ribosome from human pathogen staphylococcus aureus. | comparative structural studies of ribosomes from various organisms keep offering exciting insights on how species-specific or environment-related structural features of ribosomes may impact translation specificity and its regulation. although the importance of such features may be less obvious within more closely related organisms, their existence could account for vital yet species-specific mechanisms of translation regulation that would involve stalling, cell survival and antibiotic resistance ... | 2016 | 27906650 |
| discovery and structural characterisation of new fold type iv-transaminases exemplify the diversity of this enzyme fold. | transaminases are useful biocatalysts for the production of amino acids and chiral amines as intermediates for a broad range of drugs and fine chemicals. here, we describe the discovery and characterisation of new transaminases from microorganisms which were enriched in selective media containing (r)-amines as sole nitrogen source. while most of the candidate proteins were clearly assigned to known subgroups of the fold iv family of plp-dependent enzymes by sequence analysis and characterisation ... | 2016 | 27905516 |
| structural basis for the disaggregase activity and regulation of hsp104. | the hsp104 disaggregase is a two-ring atpase machine that rescues various forms of non-native proteins including the highly resistant amyloid fibers. the structural-mechanistic underpinnings of how the recovery of toxic protein aggregates is promoted and how this potent unfolding activity is prevented from doing collateral damage to cellular proteins are not well understood. here, we present structural and biochemical data revealing the organization of hsp104 from chaetomium thermophilum at 3.7 ... | 2016 | 27901467 |
| thermotoga maritima nusg: domain interaction mediates autoinhibition and thermostability. | nusg, the only universally conserved transcription factor, comprises an n- and a c-terminal domain (ntd, ctd) that are flexibly connected and move independently in escherichia coli and other organisms. in nusg from the hyperthermophilic bacterium thermotoga maritima (tmnusg), however, ntd and ctd interact tightly. this closed state stabilizes the ctd, but masks the binding sites for the interaction partners rho, nuse and rna polymerase (rnap), suggesting that tmnusg is autoinhibited. furthermore ... | 2016 | 27899597 |
| thermotoga maritima nusg: domain interaction mediates autoinhibition and thermostability. | nusg, the only universally conserved transcription factor, comprises an n- and a c-terminal domain (ntd, ctd) that are flexibly connected and move independently in escherichia coli and other organisms. in nusg from the hyperthermophilic bacterium thermotoga maritima (tmnusg), however, ntd and ctd interact tightly. this closed state stabilizes the ctd, but masks the binding sites for the interaction partners rho, nuse and rna polymerase (rnap), suggesting that tmnusg is autoinhibited. furthermore ... | 2016 | 27899597 |
| high-resolution phenotypic landscape of the rna polymerase ii trigger loop. | the active sites of multisubunit rna polymerases have a "trigger loop" (tl) that multitasks in substrate selection, catalysis, and translocation. to dissect the saccharomyces cerevisiae rna polymerase ii tl at individual-residue resolution, we quantitatively phenotyped nearly all tl single variants en masse. three mutant classes, revealed by phenotypes linked to transcription defects or various stresses, have distinct distributions among tl residues. we find that mutations disrupting an intra-tl ... | 2016 | 27898685 |
| trueprime is a novel method for whole-genome amplification from single cells based on tthprimpol. | sequencing of a single-cell genome requires dna amplification, a process prone to introducing bias and errors into the amplified genome. here we introduce a novel multiple displacement amplification (mda) method based on the unique dna primase features of thermus thermophilus (tth) primpol. tthprimpol displays a potent primase activity preferring dntps as substrates unlike conventional primases. a combination of tthprimpol's unique ability to synthesize dna primers with the highly processive phi ... | 2016 | 27897270 |
| redox cofactors insertion in prokaryotic molybdoenzymes occurs via a conserved folding mechanism. | a major gap of knowledge in metalloproteins is the identity of the prefolded state of the protein before cofactor insertion. this holds for molybdoenzymes serving multiple purposes for life, especially in energy harvesting. this large group of prokaryotic enzymes allows for coordination of molybdenum or tungsten cofactors (mo/w-bispgd) and fe/s clusters. here we report the structural data on a cofactor-less enzyme, the nitrate reductase respiratory complex and characterize the conformational cha ... | 2016 | 27886223 |
| a thermostable bilirubin-oxidizing enzyme from activated sludge isolated by a metagenomic approach. | a gene coding for a multicopper oxidase (bopa) was identified through the screening of a metagenomic library constructed from wastewater treatment activated sludge. the recombinant bopa protein produced in escherichia coli exhibited oxidation activity toward 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (abts) in the presence of copper, suggesting that bopa is laccase. a bioinformatic analysis of the bopa gene sequence indicated that it has a phylogenetically bacterial origin, possibly der ... | 2016 | 27885197 |
| bacterial rna polymerase-dna interaction-the driving force of gene expression and the target for drug action. | dna-dependent multisubunit rna polymerase (rnap) is the key enzyme of gene expression and a target of regulation in all kingdoms of life. it is a complex multifunctional molecular machine which, unlike other dna-binding proteins, engages in extensive and dynamic interactions (both specific and nonspecific) with dna, and maintains them over a distance. these interactions are controlled by dna sequences, dna topology, and a host of regulatory factors. here, we summarize key recent structural and b ... | 2016 | 27882317 |
| the comparatively proteomic analysis in response to cold stress in cassava plantlets. | cassava (manihot esculenta crantz) is a tropical root crop and sensitive to low temperature. however, it is poorly to know how cassava can modify its metabolism and growth to adapt to cold stress. an investigation aimed at a better understanding of cold-tolerant mechanism of cassava plantlets was carried out with the approaches of physiology and proteomics in the present study. the principal component analysis of seven physiological characteristics showed that electrolyte leakage (el), chlorophy ... | 2016 | 27881899 |
| beyond antibodies: development of a novel protein scaffold based on human chaperonin 10. | human chaperonin 10 (hcpn10) was utilised as a novel scaffold for presenting peptides of therapeutic and diagnostic significance. molecular dynamic simulations and protein sizing analyses identified a peptide linker (p1) optimal for the formation of the quarternary hcpn10 heptamer structure. hcpn10 scaffold displaying peptides targeting factor viia (ce76-p1) and cd44 (cp7) were expressed in e. coli. functional studies of ce76-p1 indicated nanomolar affinity for factor viia (3 nm) similar to the ... | 2016 | 27874025 |
| stabilization of fo/vo/ao by a radial electric field. | the membrane domain of rotary atpases (fo/vo/ao) contains a membrane-embedded rotor ring which rotates against an adjacent cation channel-forming subunit during catalysis. the mechanism that allows stabilization of the highly mobile and yet tightly connected domains during operation while not impeding rotation is unknown. remarkably, all known atpase rotor rings are filled by lipids. in the crystal structure of the rotor ring of a v-atpase from enterococcus hirae the ring filling lipids form a p ... | 2011 | 27857597 |
| similarity search for local protein structures at atomic resolution by exploiting a database management system. | a method to search for local structural similarities in proteins at atomic resolution is presented. it is demonstrated that a huge amount of structural data can be handled within a reasonable cpu time by using a conventional relational database management system with appropriate indexing of geometric data. this method, which we call geometric indexing, can enumerate ligand binding sites that are structurally similar to sub-structures of a query protein among more than 160,000 possible candidates ... | 2007 | 27857569 |
| a natural light-driven inward proton pump. | light-driven outward h(+) pumps are widely distributed in nature, converting sunlight energy into proton motive force. here we report the characterization of an oppositely directed h(+) pump with a similar architecture to outward pumps. a deep-ocean marine bacterium, parvularcula oceani, contains three rhodopsins, one of which functions as a light-driven inward h(+) pump when expressed in escherichia coli and mouse neural cells. detailed mechanistic analyses of the purified proteins reveal that ... | 2016 | 27853152 |
| boosting functionality of synthetic dna circuits with tailored deactivation. | molecular programming takes advantage of synthetic nucleic acid biochemistry to assemble networks of reactions, in vitro, with the double goal of better understanding cellular regulation and providing information-processing capabilities to man-made chemical systems. the function of molecular circuits is deeply related to their topological structure, but dynamical features (rate laws) also play a critical role. here we introduce a mechanism to tune the nonlinearities associated with individual no ... | 2016 | 27845324 |
| two proofreading steps amplify the accuracy of genetic code translation. | aminoacyl-trnas (aa-trnas) are selected by the messenger rna programmed ribosome in ternary complex with elongation factor tu (ef-tu) and gtp and then, again, in a proofreading step after gtp hydrolysis on ef-tu. we use trna mutants with different affinities for ef-tu to demonstrate that proofreading of aa-trnas occurs in two consecutive steps. first, aa-trnas in ternary complex with ef-tu·gdp are selected in a step where the accuracy increases linearly with increasing aa-trna affinity to ef-tu. ... | 2016 | 27837019 |
| identification of ybey-protein interactions involved in 16s rrna maturation and stress regulation in escherichia coli. | ybey is part of a core set of rnases in escherichia coli and other bacteria. this highly conserved endoribonuclease has been implicated in several important processes such as 16s rrna 3' end maturation, 70s ribosome quality control, and regulation of mrnas and small noncoding rnas, thereby affecting cellular viability, stress tolerance, and pathogenic and symbiotic behavior of bacteria. thus, ybey likely interacts with numerous protein or rna partners that are involved in various aspects of cell ... | 2016 | 27834201 |
| dcia is an ancestral replicative helicase operator essential for bacterial replication initiation. | delivery of the replicative helicase onto dna is an essential step in the initiation of replication. in bacteria, dnac (in escherichia coli) and dnai (in bacillus subtilis) are representative of the two known mechanisms that assist the replicative helicase at this stage. here, we establish that these two strategies cannot be regarded as prototypical of the bacterial domain since dnac and dnai (dna[ci]) are present in only a few bacterial phyla. we show that dna[ci] was domesticated at least seve ... | 2016 | 27830752 |
| thermus and the pink discoloration defect in cheese. | a dna sequencing-based strategy was applied to study the microbiology of continental-type cheeses with a pink discoloration defect. the basis for this phenomenon has remained elusive, despite decades of research. the bacterial composition of cheese containing the defect was compared to that of control cheese using 16s rrna gene and shotgun metagenomic sequencing as well as quantitative pcr (qpcr). throughout, it was apparent that thermus, a carotenoid-producing genus, was present at higher level ... | 2016 | 27822529 |
| cryo-em study of start codon selection during archaeal translation initiation. | eukaryotic and archaeal translation initiation complexes have a common structural core comprising e/aif1, e/aif1a, the ternary complex (tc, e/aif2-gtp-met-trnai(met)) and mrna bound to the small ribosomal subunit. e/aif2 plays a crucial role in this process but how this factor controls start codon selection remains unclear. here, we present cryo-em structures of the full archaeal 30s initiation complex showing two conformational states of the tc. in the first state, the tc is bound to the riboso ... | 2016 | 27819266 |
| crystal structures of the atp-binding and adp-release dwells of the v1 rotary motor. | v1-atpases are highly conserved atp-driven rotary molecular motors found in various membrane systems. we recently reported the crystal structures for the enterococcus hirae a3b3df (v1) complex, corresponding to the catalytic dwell state waiting for atp hydrolysis. here we present the crystal structures for two other dwell states obtained by soaking nucleotide-free v1 crystals in adp. in the presence of 20 μm adp, two adp molecules bind to two of three binding sites and cooperatively induce confo ... | 2016 | 27807367 |
| avilamycin and evernimicin induce structural changes in rproteins ul16 and ctc that enhance the inhibition of a-site trna binding. | two structurally unique ribosomal antibiotics belonging to the orthosomycin family, avilamycin and evernimicin, possess activity against enterococci, staphylococci, and streptococci, and other gram-positive bacteria. here, we describe the high-resolution crystal structures of the eubacterial large ribosomal subunit in complex with them. their extended binding sites span the a-trna entrance corridor, thus inhibiting protein biosynthesis by blocking the binding site of the a-trna elbow, a mechanis ... | 2016 | 27791159 |
| in vitro engineering of novel bioactivity in the natural enzymes. | enzymes catalyze various biochemical functions with high efficiency and specificity. in vitro design of the enzyme leads to novel bioactivity in this natural biomolecule that give answers of some vital questions like crucial residues in binding with substrate, molecular evolution, cofactor specificity etc. enzyme engineering technology involves directed evolution, rational designing, semi-rational designing, and structure-based designing using chemical modifications. similarly, combined computat ... | 2016 | 27774447 |
| birth of archaeal cells: molecular phylogenetic analyses of g1p dehydrogenase, g3p dehydrogenases, and glycerol kinase suggest derived features of archaeal membranes having g1p polar lipids. | bacteria and eukarya have cell membranes with sn-glycerol-3-phosphate (g3p), whereas archaeal membranes contain sn-glycerol-1-phosphate (g1p). determining the time at which cells with either g3p-lipid membranes or g1p-lipid membranes appeared is important for understanding the early evolution of terrestrial life. to clarify this issue, we reconstructed molecular phylogenetic trees of g1pdh (g1p dehydrogenase; egsa/aram) which is responsible for g1p synthesis and g3pdhs (g3p dehydrogenase; gpsa a ... | 2016 | 27774041 |
| adaptation in bacillus cereus: from stress to disease. | bacillus cereus is a food-borne pathogen that causes diarrheal disease in humans. after ingestion, b. cereus experiences in the human gastro-intestinal tract abiotic physical variables encountered in food, such as acidic ph in the stomach and changing oxygen conditions in the human intestine. b. cereus responds to environmental changing conditions (stress) by reversibly adjusting its physiology to maximize resource utilization while maintaining structural and genetic integrity by repairing and m ... | 2016 | 27757102 |
| microcystin-bound protein patterns in different cultures of microcystis aeruginosa and field samples. | micocystin (mc) exists in microcystis cells in two different forms, free and protein-bound. we examined the dynamic change in extracellular free mcs, intracellular free mcs and protein-bound mcs in both batch cultures and semi-continuous cultures, using high performance liquid chromatography and western blot. the results showed that the free mc per cell remained constant, while the quantity of protein-bound mcs increased with the growth of microcystis cells in both kinds of culture. significant ... | 2016 | 27754336 |
| target and non-target site mechanisms developed by glyphosate-resistant hairy beggarticks (bidens pilosa l.) populations from mexico. | in 2014 hairy beggarticks (bidens pilosa l.) has been identified as being glyphosate-resistant in citrus orchards from mexico. the target and non-target site mechanisms involved in the response to glyphosate of two resistant populations (r1 and r2) and one susceptible (s) were studied. experiments of dose-response, shikimic acid accumulation, uptake-translocation, enzyme activity and 5-enolpyruvyl shikimate-3-phosphate synthase (epsps) gene sequencing were carried out in each population. the r1 ... | 2016 | 27752259 |
| structures and stabilization of kinetoplastid-specific split rrnas revealed by comparing leishmanial and human ribosomes. | the recent success in ribosome structure determination by cryoem has opened the door to defining structural differences between ribosomes of pathogenic organisms and humans and to understand ribosome-targeting antibiotics. here, by direct electron-counting cryoem, we have determined the structures of the leishmania donovani and human ribosomes at 2.9 å and 3.6 å, respectively. our structure of the leishmanial ribosome elucidates the organization of the six fragments of its large subunit rrna (as ... | 2016 | 27752045 |
| characterization of a highly thermostable and organic solvent-tolerant copper-containing polyphenol oxidase with dye-decolorizing ability from kurthia huakuii lam0618t. | laccases are green biocatalysts that possess attractive advantages for the treatment of resistant environmental pollutants and dye effluents. a putative laccase-like gene, laclk, encoding a protein of 29.3 kda and belonging to the cu-oxidase_4 superfamily, was cloned and overexpressed in escherichia coli. the purified recombinant protein laclk (laclk) was able to oxidize typical laccase substrates such as 2,6-dimethoxyphenol and l-dopamine. the characteristic adsorption maximums of typical lacca ... | 2016 | 27741324 |
| analysis of the core genome and pan-genome of autotrophic acetogenic bacteria. | acetogens are obligate anaerobic bacteria capable of reducing carbon dioxide (co2) to multicarbon compounds coupled to the oxidation of inorganic substrates, such as hydrogen (h2) or carbon monoxide (co), via the wood-ljungdahl pathway. owing to the metabolic capability of co2 fixation, much attention has been focused on understanding the unique pathways associated with acetogens, particularly their metabolic coupling of co2 fixation to energy conservation. most known acetogens are phylogenetica ... | 2016 | 27733845 |
| metagenomics of thermophiles with a focus on discovery of novel thermozymes. | microbial populations living in environments with temperatures above 50°c (thermophiles) have been widely studied, increasing our knowledge in the composition and function of these ecological communities. since these populations express a broad number of heat-resistant enzymes (thermozymes), they also represent an important source for novel biocatalysts that can be potentially used in industrial processes. the integrated study of the whole-community dna from an environment, known as metagenomics ... | 2016 | 27729905 |
| functional characterization of a csor-cuea divergon in bradyrhizobium liaoningense ccnwsx0360, involved in copper, zinc and cadmium cotolerance. | random mutagenesis in a symbiotic nitrogen-fixing bradyrhizobium liaoningense ccnwsx0360 (bln0360) using tn5 identified five copper (cu) resistance-related genes. they were functionally sorted into three groups: transmembrane transport (cuea and tolc); oxidation (copa); and protection of the membrane barrier (lpte and ctpa). the gene cuea, together with the upstream csor (cu-sensitive operon repressor), constituted a csor-cuea divergon which plays a crucial role in cu homeostasis. deletion of cu ... | 2016 | 27725778 |
| structural characterization of antibiotic self-immunity trna synthetase in plant tumour biocontrol agent. | antibiotic-producing microbes evolved self-resistance mechanisms to avoid suicide. the biocontrol agrobacterium radiobacter k84 secretes the trojan horse antibiotic agrocin 84 that is selectively transported into the plant pathogen a. tumefaciens and processed into the toxin tm84. we previously showed that tm84 employs a unique trna-dependent mechanism to inhibit leucyl-trna synthetase (leurs), while the tm84-producer prevents self-poisoning by expressing a resistant leurs agnb2. we now identify ... | 2016 | 27713402 |
| mechanism of ph-dependent activation of the sodium-proton antiporter nhaa. | escherichia coli nhaa is a prototype sodium-proton antiporter, which has been extensively characterized by x-ray crystallography, biochemical and biophysical experiments. however, the identities of proton carriers and details of ph-regulated mechanism remain controversial. here we report constant ph molecular dynamics data, which reveal that nhaa activation involves a net charge switch of a ph sensor at the entrance of the cytoplasmic funnel and opening of a hydrophobic gate at the end of the fu ... | 2016 | 27708266 |
| nusg inhibits rna polymerase backtracking by stabilizing the minimal transcription bubble. | universally conserved factors from nusg family bind at the upstream fork junction of transcription elongation complexes and modulate rna synthesis in response to translation, processing, and folding of the nascent rna. escherichia coli nusg enhances transcription elongation in vitro by a poorly understood mechanism. here we report that e. coli nusg slows gre factor-stimulated cleavage of the nascent rna, but does not measurably change the rates of single nucleotide addition and translocation by ... | 2016 | 27697152 |
| ns-μs time-resolved step-scan ftir of ba₃ oxidoreductase from thermus thermophilus: protonic connectivity of w941-w946-w927. | time-resolved step-scan ftir spectroscopy has been employed to probe the dynamics of the ba₃ oxidoreductase from thermus thermophilus in the ns-μs time range and in the ph/pd 6-9 range. the data revealed a ph/pd sensitivity of the d372 residue and of the ring-a propionate of heme a₃. based on the observed transient changes a model in which the protonic connectivity of w941-w946-927 to the d372 and the ring-a propionate of heme a₃ is described. | 2016 | 27690021 |
| thermus thermophilus as a source of thermostable lipolytic enzymes. | lipolytic enzymes, esterases (ec 3.1.1.1) and lipases (ec 3.1.1.3), catalyze the hydrolysis of ester bonds between alcohols and carboxylic acids, and its formation in organic media. at present, they represent about 20% of commercialized enzymes for industrial use. lipolytic enzymes from thermophilic microorganisms are preferred for industrial use to their mesophilic counterparts, mainly due to higher thermostability and resistance to several denaturing agents. however, the production at an indus ... | 2015 | 27682117 |
| how to show the real microbial biodiversity? a comparison of seven dna extraction methods for bacterial population analyses in matrices containing highly charged natural nanoparticles. | a dna extraction that comprises the dna of all available taxa in an ecosystem is an essential step in population analysis, especially for next generation sequencing applications. many nanoparticles as well as naturally occurring clay minerals contain charged surfaces or edges that capture negatively charged dna molecules after cell lysis within dna extraction. depending on the methodology of dna extraction, this phenomenon causes a shift in detection of microbial taxa in ecosystems and a possibl ... | 2015 | 27682112 |
| role of nad⁺-dependent malate dehydrogenase in the metabolism of methylomicrobium alcaliphilum 20z and methylosinus trichosporium ob3b. | we have expressed the l-malate dehydrogenase (mdh) genes from aerobic methanotrophs methylomicrobium alcaliphilum 20z and methylosinus trichosporium ob3b as his-tagged proteins in escherichia coli. the substrate specificities, enzymatic kinetics and oligomeric states of the mdhs have been characterized. both mdhs were nad⁺-specific and thermostable enzymes not affected by metal ions or various organic metabolites. the mdh from m. alcaliphilum 20z was a homodimeric (2 × 35 kda) enzyme displaying ... | 2015 | 27682078 |
| uniformity of peptide release is maintained by methylation of release factors. | termination of protein synthesis on the ribosome is catalyzed by release factors (rfs), which share a conserved glycine-glycine-glutamine (ggq) motif. the glutamine residue is methylated in vivo, but a mechanistic understanding of its contribution to hydrolysis is lacking. here, we show that the modification, apart from increasing the overall rate of termination on all dipeptides, substantially increases the rate of peptide release on a subset of amino acids. in the presence of unmethylated rfs, ... | 2016 | 27681416 |
| new insight into isoprenoids biosynthesis process and future prospects for drug designing in plasmodium. | the mep (methyl erythritol phosphate) isoprenoids biosynthesis pathway is an attractive drug target to combat malaria, due to its uniqueness and indispensability for the parasite. it is functional in the apicoplast of plasmodium and its products get transported to the cytoplasm, where they participate in glycoprotein synthesis, electron transport chain, trna modification and several other biological processes. several compounds have been tested against the enzymes involved in this pathway and am ... | 2016 | 27679614 |
| unexpected functional implication of a stable succinimide in the structural stability of methanocaldococcus jannaschii glutaminase. | protein ageing is often mediated by the formation of succinimide intermediates. these short-lived intermediates derive from asparaginyl deamidation and aspartyl dehydration and are rapidly converted into β-aspartyl or d-aspartyl residues. here we report the presence of a highly stable succinimide intermediate in the glutaminase subunit of gmp synthetase from the hyperthermophile methanocaldoccocus jannaschii. by comparing the biophysical properties of the wild-type protein and of several mutants ... | 2016 | 27677693 |
| n-acetylgalatosamine-mediated regulation of the aga operon by agar in streptococcus pneumoniae. | here, we analyze the transcriptomic response of streptococcus pneumoniae d39 to n-acetylgalactosamine (naga). transcriptome comparison of s. pneumoniae d39 grown in nagam17 (0.5% naga + m17) to that grown in gm17 (0.5% glucose + m17) revealed the elevated expression of various carbon metabolic genes/operons, including a pts operon (denoted here as the aga operon), which is putatively involved in naga transport and utilization, in the presence of naga. we further studied the role of a gntr-family ... | 2016 | 27672623 |
| quantifying the biases in metagenome mining for realistic assessment of microbial ecology of naturally fermented foods. | cultivation-independent investigation of microbial ecology is biased by the dna extraction methods used. we aimed to quantify those biases by comparative analysis of the metagenome mined from four diverse naturally fermented foods (bamboo shoot, milk, fish, soybean) using eight different dna extraction methods with different cell lysis principles. our findings revealed that the enzymatic lysis yielded higher eubacterial and yeast metagenomic dna from the food matrices compared to the widely used ... | 2016 | 27669673 |
| the novel aminomethylcycline omadacycline has high specificity for the primary tetracycline-binding site on the bacterial ribosome. | omadacycline is an aminomethylcycline antibiotic with potent activity against many gram-positive and gram-negative pathogens, including strains carrying the major efflux and ribosome protection resistance determinants. this makes it a promising candidate for therapy of severe infectious diseases. omadacycline inhibits bacterial protein biosynthesis and competes with tetracycline for binding to the ribosome. its interactions with the 70s ribosome were, therefore, analyzed in great detail and comp ... | 2016 | 27669321 |
| molecular insights into substrate recognition and catalytic mechanism of the chaperone and fkbp peptidyl-prolyl isomerase slyd. | peptidyl-prolyl isomerases (ppiases) catalyze cis/trans isomerization of peptidyl-prolyl bonds, which is often rate-limiting for protein folding. slyd is a two-domain enzyme containing both a ppiase fk506-binding protein (fkbp) domain and an insert-in-flap (if) chaperone domain. to date, the interactions of these domains with unfolded proteins have remained rather obscure, with structural information on binding to the fkbp domain being limited to complexes involving various inhibitor compounds o ... | 2016 | 27664121 |
| large-scale movements of if3 and trna during bacterial translation initiation. | in bacterial translational initiation, three initiation factors (ifs 1-3) enable the selection of initiator trna and the start codon in the p site of the 30s ribosomal subunit. here, we report 11 single-particle cryo-electron microscopy (cryoem) reconstructions of the complex of bacterial 30s subunit with initiator trna, mrna, and ifs 1-3, representing different steps along the initiation pathway. if1 provides key anchoring points for if2 and if3, thereby enhancing their activities. if2 position ... | 2016 | 27662086 |
| crystal structures of two isozymes of citrate synthase from sulfolobus tokodaii strain 7. | thermoacidophilic archaeon sulfolobus tokodaii strain 7 has two citrate synthase genes (st1805-cs and st0587-cs) in the genome with 45% sequence identity. because they exhibit similar optimal temperatures of catalytic activity and thermal inactivation profiles, we performed structural comparisons between these isozymes to elucidate adaptation mechanisms to high temperatures in thermophilic css. the crystal structures of st1805-cs and st0587-cs were determined at 2.0 å and 2.7 å resolutions, resp ... | 2016 | 27656296 |
| the nucleotide excision repair pathway protects borrelia burgdorferi from nitrosative stress in ixodes scapularis ticks. | the lyme disease spirochete borrelia burgdorferi encounters a wide range of environmental conditions as it cycles between ticks of the genus ixodes and its various mammalian hosts. reactive oxygen species (ros) and reactive nitrogen species (rns) are potent antimicrobial molecules generated during the innate immune response to infection, however, it is unclear whether ros and rns pose a significant challenge to b. burgdorferi in vivo. in this study, we screened a library of b. burgdorferi strain ... | 2016 | 27656169 |
| avoidance of stochastic rna interactions can be harnessed to control protein expression levels in bacteria and archaea. | a critical assumption of gene expression analysis is that mrna abundances broadly correlate with protein abundance, but these two are often imperfectly correlated. some of the discrepancy can be accounted for by two important mrna features: codon usage and mrna secondary structure. we present a new global factor, called mrna:ncrna avoidance, and provide evidence that avoidance increases translational efficiency. we also demonstrate a strong selection for the avoidance of stochastic mrna:ncrna in ... | 2016 | 27642845 |
| molecular basis of cobalamin-dependent rna modification. | queuosine (q) was discovered in the wobble position of a transfer rna (trna) 47 years ago, yet the final biosynthetic enzyme responsible for q-maturation, epoxyqueuosine (oq) reductase (queg), was only recently identified. queg is a cobalamin (cbl)-dependent, [4fe-4s] cluster-containing protein that produces the hypermodified nucleoside q in situ on four trnas. to understand how queg is able to perform epoxide reduction, an unprecedented reaction for a cbl-dependent enzyme, we have determined a ... | 2016 | 27638883 |
| origin of a folded repeat protein from an intrinsically disordered ancestor. | repetitive proteins are thought to have arisen through the amplification of subdomain-sized peptides. many of these originated in a non-repetitive context as cofactors of rna-based replication and catalysis, and required the rna to assume their active conformation. in search of the origins of one of the most widespread repeat protein families, the tetratricopeptide repeat (tpr), we identified several potential homologs of its repeated helical hairpin in non-repetitive proteins, including the put ... | 2016 | 27623012 |
| specific internalisation of gold nanoparticles into engineered porous protein cages via affinity binding. | porous protein cages are supramolecular protein self-assemblies presenting pores that allow the access of surrounding molecules and ions into their core in order to store and transport them in biological environments. protein cages' pores are attractive channels for the internalisation of inorganic nanoparticles and an alternative for the preparation of hybrid bioinspired nanoparticles. however, strategies based on nanoparticle transport through the pores are largely unexplored, due to the diffi ... | 2016 | 27622533 |
| parb partition proteins: complex formation and spreading at bacterial and plasmid centromeres. | in bacteria, active partition systems contribute to the faithful segregation of both chromosomes and low-copy-number plasmids. each system depends on a site-specific dna binding protein to recognize and assemble a partition complex at a centromere-like site, commonly called pars. many plasmid, and all chromosomal centromere-binding proteins are dimeric helix-turn-helix dna binding proteins, which are commonly named parb. although the overall sequence conservation among parbs is not high, the pro ... | 2016 | 27622187 |
| inhibition of bacterial rnase p rna by phenothiazine derivatives. | there is a need to identify novel scaffolds and targets to develop new antibiotics. methylene blue is a phenothiazine derivative, and it has been shown to possess anti-malarial and anti-trypanosomal activities. here, we show that different phenothiazine derivatives and pyronine g inhibited the activities of three structurally different bacterial rnase p rnas (rprs), including that from mycobacterium tuberculosis, with ki values in the lower μm range. interestingly, three antipsychotic phenothiaz ... | 2016 | 27618117 |
| structures of type iv pilins from thermus thermophilus demonstrate similarities with type ii secretion system pseudopilins. | type iv pilins are proteins which form polymers that extend from the surface of the bacterial cell; they are involved in mediating a wide variety of functions, including adhesion, motility and natural competence. here we describe the determination of the crystal structures of three type iva pilins proteins from the thermophile thermus thermophilus. they form part of a cluster of pilus-like proteins within the genome; our results show that one, tt1222, is very closely related to the main structur ... | 2016 | 27612581 |
| identification of essential genes in the salmonella phage spn3us reveals novel insights into giant phage head structure and assembly. | giant tailed bacterial viruses, or phages, such as pseudomonas aeruginosa phage ϕkz, have long genomes packaged into large, atypical virions. many aspects of ϕkz and related phage biology are poorly understood, mostly due to the fact that the functions of the majority of their proteins are unknown. we hypothesized that the salmonella enterica phage spn3us could be a useful model phage to address this gap in knowledge. the 240-kb spn3us genome shares a core set of 91 genes with ϕkz and related ph ... | 2016 | 27605673 |
| purification, characterization, cytotoxicity and anticancer activities of l-asparaginase, anti-colon cancer protein, from the newly isolated alkaliphilic streptomyces fradiae neae-82. | l-asparaginase is an important enzyme as therapeutic agents used in combination with other drugs in the treatment of acute lymphoblastic leukemia. a newly isolated actinomycetes strain, streptomyces sp. neae-82, was potentially producing extracellular l-asparaginase, it was identified as streptomyces fradiae neae-82, sequencing product was deposited in the genbank database under accession number kj467538. l-asparaginase was purified from the crude enzyme using ammonium sulfate precipitation, dia ... | 2016 | 27605431 |
| atomic structure of an archaeal gan suggests its dual roles as an exonuclease in dna repair and a cmg component in dna replication. | in eukaryotic dna replication initiation, hexameric mcm (mini-chromosome maintenance) unwinds the template double-stranded dna to form the replication fork. mcm is activated by two proteins, cdc45 and gins, which constitute the 'cmg' unwindosome complex together with the mcm core. the archaeal dna replication system is quite similar to that of eukaryotes, but only limited knowledge about the dna unwinding mechanism is available, from a structural point of view. here, we describe the crystal stru ... | 2016 | 27599844 |
| vapcs of mycobacterium tuberculosis cleave rnas essential for translation. | the major human pathogen mycobacterium tuberculosis can survive in the host organism for decades without causing symptoms. a large cohort of toxin-antitoxin (ta) modules contribute to this persistence. of these, 48 ta modules belong to the vapbc (virulence associated protein) gene family. vapc toxins are pin domain endonucleases that, in enterobacteria, inhibit translation by site-specific cleavage of initiator trna. in contrast, vapc20 of m. tuberculosis inhibits translation by site-specific cl ... | 2016 | 27599842 |
| eiger detector: application in macromolecular crystallography. | the development of single-photon-counting detectors, such as the pilatus, has been a major recent breakthrough in macromolecular crystallography, enabling noise-free detection and novel data-acquisition modes. the new eiger detector features a pixel size of 75 × 75 µm, frame rates of up to 3000 hz and a dead time as low as 3.8 µs. an eiger 1m and eiger 16m were tested on swiss light source beamlines x10sa and x06sa for their application in macromolecular crystallography. the combination of fast ... | 2016 | 27599736 |
| chemistry and molecular dynamics simulations of heme b-hemq and coproheme-hemq. | recently, a novel pathway for heme b biosynthesis in gram-positive bacteria has been proposed. the final poorly understood step is catalyzed by an enzyme called hemq and includes two decarboxylation reactions leading from coproheme to heme b. coproheme has been suggested to act as both substrate and redox active cofactor in this reaction. in the study presented here, we focus on hemqs from listeria monocytogenes (lmhemq) and staphylococcus aureus (sahemq) recombinantly produced as apoproteins in ... | 2016 | 27599156 |
| the hemq coprohaem decarboxylase generates reactive oxygen species: implications for the evolution of classical haem biosynthesis. | bacteria require a haem biosynthetic pathway for the assembly of a variety of protein complexes, including cytochromes, peroxidases, globins, and catalase. haem is synthesised via a series of tetrapyrrole intermediates, including non-metallated porphyrins, such as protoporphyrin ix, which is well known to generate reactive oxygen species in the presence of light and oxygen. staphylococcus aureus has an ancient haem biosynthetic pathway that proceeds via the formation of coproporphyrin iii, a les ... | 2016 | 27597779 |
| convergent evolution of trna gene targeting preferences in compact genomes. | in gene-dense genomes, mobile elements are confronted with highly selective pressure to amplify without causing excessive damage to the host. the targeting of trna genes as potentially safe integration sites has been developed by retrotransposons in various organisms such as the social amoeba dictyostelium discoideum and the yeast saccharomyces cerevisiae. in d. discoideum, trna gene-targeting retrotransposons have expanded to approximately 3 % of the genome. recently obtained genome sequences o ... | 2016 | 27583033 |
| crystal structure of the two-subunit trna m(1)a58 methyltransferase trm6-trm61 from saccharomyces cerevisiae. | the n(1) methylation of adenine at position 58 (m(1)a58) of trna is an important post-transcriptional modification, which is vital for maintaining the stability of the initiator methionine trnai(met). in eukaryotes, this modification is performed by the trm6-trm61 holoenzyme. to understand the molecular mechanism that underlies the cooperation of trm6 and trm61 in the methyl transfer reaction, we determined the crystal structure of trm6-trm61 holoenzyme from saccharomyces cerevisiae in the prese ... | 2016 | 27582183 |
| rna regulators responding to ribosomal protein s15 are frequent in sequence space. | there are several natural examples of distinct rna structures that interact with the same ligand to regulate the expression of homologous genes in different organisms. one essential question regarding this phenomenon is whether such rna regulators are the result of convergent or divergent evolution. are the rnas derived from some common ancestor and diverged to the point where we cannot identify the similarity, or have multiple solutions to the same biological problem arisen independently? a key ... | 2016 | 27580716 |
| cloning, expression, and characterization of a novel thermophilic monofunctional catalase from geobacillus sp. chb1. | catalases are widely used in many scientific areas. a catalase gene (kat) from geobacillus sp. chb1 encoding a monofunctional catalase was cloned and recombinant expressed in escherichia coli (e. coli), which was the first time to clone and express this type of catalase of genus geobacillus strains as far as we know. this kat gene was 1,467 bp in length and encoded a catalase with 488 amino acid residuals, which is only 81% similar to the previously studied bacillus sp. catalase in terms of amin ... | 2016 | 27579320 |