| crystal structure studies on sulfur oxygenase reductase from acidianus tengchongensis. | sulfur oxygenase reductase (sor) simultaneously catalyzes oxidation and reduction of elemental sulfur to produce sulfite, thiosulfate, and sulfide in the presence of molecular oxygen. in this study, crystal structures of wild type and mutants of sor from acidianus tengchongensis (sor-at) in two different crystal forms were determined and it was observed that 24 identical sor monomers form a hollow sphere. within the icosatetramer sphere, the tetramer and trimer channels were proposed as the path ... | 2008 | 18329378 |
| an extracellular tetrathionate hydrolase from the thermoacidophilic archaeon acidianus ambivalens with an activity optimum at ph 1. | background: the thermoacidophilic and chemolithotrophic archaeon acidianus ambivalens is routinely grown with sulfur and co(2)-enriched air. we had described a membrane-bound, tetrathionate (tt) forming thiosulfate:quinone oxidoreductase. here we describe the first tt hydrolase (tth) from archaea. results: a. ambivalens cells grown aerobically with tt as sole sulfur source showed doubling times of 9?h and final cell densities of up to 8?×?10(8)/ml. tth activity (˜0.28?u/mg protein) was found in ... | 2011 | 21747790 |
| cell cycle characteristics of crenarchaeota: unity among diversity. | the hyperthermophilic archaea acidianus hospitalis, aeropyrum pernix, pyrobaculum aerophilum, pyrobaculum calidifontis, and sulfolobus tokodaii representing three different orders in the phylum crenarchaeota were analyzed by flow cytometry and combined phase-contrast and epifluorescence microscopy. the overall organization of the cell cycle was found to be similar in all species, with a short prereplicative period and a dominant postreplicative period that accounted for 64 to 77% of the generati ... | 2008 | 18502873 |
| The Sulfur Oxygenase Reductase from the Mesophilic Bacterium Halothiobacillus neapolitanus is a Highly Active Thermozyme. | A biochemical, biophysical and phylogenetic study of the sulfur oxygenase reductase (SOR) from the mesophilic Gammaproteobacterium Halothiobacillus neapolitanus (HnSOR) was performed in order to determine the structural and biochemical properties. SOR proteins from 14 predominantly chemolithoautotrophic bacterial and archaeal species are currently available in public databases. Sequence alignment and phylogenetic analysis showed that they form a coherent protein family. The HnSOR purified from E ... | 2011 | 22139503 |
| on the relative contribution of ionic interactions over iron-sulfur clusters to ferredoxin stability. | metal centres play an important structural role in maintaining the native conformation of a protein. here we use biophysical methods to investigate what is the relative contribution of iron-sulfur clusters in respect to ionic interactions in a thermophilic di-cluster ferredoxin model. changes in protonation affect both the stability and the conformational dynamics of the protein fold. in the ph 5.5-8 interval, the protein has a high melting temperature (t(m) approximately 120 degrees c), which d ... | 2008 | 18534203 |
| aaa atpase p529 of acidianus two-tailed virus atv and host receptor recognition. | the two structural domains of p529, a predicted aaa atpase of acidianus two-tailed virus (atv), were expressed and purified. the n-terminal domain was demonstrated by loss-of-function mutations to carry atpase activity with a temperature optimum of 60°c. this domain also showed dna binding activity that was stronger for the whole protein and was weakened in the presence of atp. the c-terminal domain exhibits mg(2+)-dependent endonuclease activity that was eliminated by site-directed mutagenesis ... | 2011 | 21982819 |
| structure and coordination of cub in the acidianus ambivalens aa3 quinol oxidase heme-copper center. | the coordination environment of the cu(b) center of the quinol oxidase from acidianus ambivalens, a type b heme-copper oxygen reductase, was investigated by fourier transform (ft) ir and extended x-ray absorption fine structure (exafs) spectroscopy. the comparative structural chemistry of dinuclear fe-cu sites of the different types of oxygen reductases is of great interest. fully reduced a. ambivalens quinol oxidase binds co at the heme a (3) center, with nu(co)=1,973 cm(-1). on photolysis, the ... | 2005 | 16163550 |
| ferrous iron- and sulfur-induced genes in sulfolobus metallicus. | genes of sulfolobus metallicus that appeared to be upregulated in relation to growth on either ferrous iron or sulfur were identified using subtractive hybridization of cdnas. the genes upregulated during growth on ferrous iron were found in a cluster, and most were predicted to encode membrane proteins. quantitative reverse transcription-pcr of cdna showed upregulation of most of these genes during growth on ferrous iron and pyrite compared to results during growth on sulfur. the highest expres ... | 2007 | 17322327 |
| chaperone role for proteins p618 and p892 in the extracellular tail development of acidianus two-tailed virus. | the crenarchaeal acidianus two-tailed virus (atv) undergoes a remarkable morphological development, extracellularly and independently of host cells, by growing long tails at each end of a spindle-shaped virus particle. initial work suggested that an intermediate filament-like protein, p800, is involved in this process. we propose that an additional chaperone system is required, consisting of a moxr-type aaa atpase (p618) and a von willebrand domain a (vwa)-containing cochaperone, p892. both prot ... | 2011 | 21367903 |
| genomic analysis of acidianus hospitalis w1 a host for studying crenarchaeal virus and plasmid life cycles. | the acidianus hospitalis w1 genome consists of a minimally sized chromosome of about 2.13 mb and a conjugative plasmid pah1 and it is a host for the model filamentous lipothrixvirus afv1. the chromosome carries three putative replication origins in conserved genomic regions and two large regions where non-essential genes are clustered. within these variable regions, a few orphan orfb and other elements of the is200/607/605 family are concentrated with a novel class of mite-like repeat elements. ... | 2011 | 21607549 |
| novel archaeal plasmid pah1 and its interactions with the lipothrixvirus afv1. | at present very little is known about interactions between extrachromosomal genetic elements in archaea. here we describe an acidianus strain which carries naturally a novel 28 kb conjugative plasmid-like element, pah1, and also serves as a laboratory host for lipothrixvirus afv1. in an attempt to establish a system for studying plasmid-virus interactions we characterized the genome of pah1 which closely resembles those of the sulfolobus conjugative plasmids parn3 and parn4. pah1 integrates site ... | 2009 | 19007417 |
| the community dynamics of major bioleaching microorganisms during chalcopyrite leaching under the effect of organics. | to determine the effect of organics (yeast extract) on microbial community during chalcopyrite bioleaching at different temperature, real-time polymerase chain reaction (pcr) was employed to analyze community dynamics of major bacteria applied in bioleaching. the results showed that yeast extract exerted great impact on microbial community, and therefore influencing bioleaching rate. to be specific, yeast extract was adverse to this bioleaching process at 30°c due to decreased proportion of impo ... | 2011 | 21638040 |
| kinetics of ferrous iron oxidation by batch and continuous cultures of thermoacidophilic archaea at extremely low ph of 1.1-1.3. | the extreme acid conditions required for scorodite (feaso(4)·2h(2)o) biomineralization (ph below 1.3) are suboptimal for growth of most thermoacidophilic archaea. with the objective to develop a continuous process suitable for biomineral production, this research focuses on growth kinetics of thermoacidophilic archaea at low ph conditions. ferrous iron oxidation rates were determined in batch-cultures at ph 1.3 and a temperature of 75°c for acidianus sulfidivorans, metallosphaera prunea and a mi ... | 2011 | 21751006 |
| crystal structure of afv1-102, a protein from the acidianus filamentous virus 1. | viruses infecting hyperthermophilic archaea have intriguing morphologies and genomic properties. the vast majority of their genes do not have homologs other than in other hyperthermophilic viruses, and the biology of these viruses is poorly understood. as part of a structural genomics project on the proteins of these viruses, we present here the structure of a 102 amino acid protein from acidianus filamentous virus 1 (afv1-102). the structure shows that it is made of two identical motifs that ha ... | 2009 | 19319936 |
| structural and functional insights into sulfide:quinone oxidoreductase. | a sulfide:quinone oxidoreductase (sqr) was isolated from the membranes of the hyperthermoacidophilic archaeon acidianus ambivalens, and its x-ray structure, the first reported for an sqr, was determined to 2.6 a resolution. this enzyme was functionally and structurally characterized and was shown to have two redox active sites: a covalently bound fad and an adjacent pair of cysteine residues. most interestingly, the x-ray structure revealed the presence of a chain of three sulfur atoms bridging ... | 2009 | 19438211 |
| the thermo- and acido-stable orf-99 from the archaeal virus afv1. | acidianus filamentous virus 1 (afv1), isolated from acidic hot springs, is an enveloped lipid-containing archaeal filamentous virus with a linear double-stranded dna genome. it infects acidianus, which is a hyperthermostable archaea growing at 85 degrees c and acidic phs, below ph 3. afv1-99, a protein of 99 amino acids of unknown function, has homologues in the archaeal virus families lipothrixviridae and rudiviridae. we determined the crystal structure of afv1-99 at 2.05 a resolution. afv1-99 ... | 2009 | 19472363 |
| viruses in acidic geothermal environments of the kamchatka peninsula. | screening for viruses in samples taken from acidic hot springs of kamchatka (russia) revealed a collection of morphotypes, including linear, spherical and complex fusiform shapes, which show partial similarity to those found in acidic geothermal environments in other geographical locations. one of the viruses, acidianus filamentous virus 9, afv9, was isolated and its structure and genome were studied in detail. | 2008 | 18565736 |
| acidianus, sulfolobus and metallosphaera surface layers: structure, composition and gene expression. | the cell walls of sulfolobales species consist of proteinaceous s-layers assembled from two polypeptides, slaa and slab. we isolated the large s-layer protein of acidianus ambivalens and both s-layer subunits of sulfolobus solfataricus and metallosphaera sedula, respectively. the slaab genes, lying adjacently in the chromosomes, are constitutively transcribed as bicistronic operons in a. ambivalens and s. solfataricus. a smaller slaa transcript appeared in northern hybridizations of a. ambivalen ... | 2009 | 19522740 |
| probing the archaeal diversity of a mixed thermophilic bioleaching culture by tgge and fish. | the archaeal community present in a sample of mixed thermophilic culture-b (mtc-b) from a laboratory-scale thermophilic bioleaching reactor was investigated by temperature gradient gel electrophoresis (tgge) and fluorescence in situ hybridisation (fish). both techniques were specifically adapted for use on native state bioleaching samples, with a view to establishing convenient means for monitoring culture composition. using the tgge protocol developed, the relative species composition of the th ... | 2009 | 19541445 |
| microbial diversity of boron-rich volcanic hot springs of st. lucia, lesser antilles. | the volcanic sulphur springs, st. lucia, present an extreme environment due to high temperatures, low ph values, and high concentrations of sulfate and boron. st. lucia offers some unique geochemical characteristics that may shape the microbial communities within the sulphur springs area. we chose six pools representing a range of geochemical characteristics for detailed microbial community analyses. chemical concentrations varied greatly between sites. microbial diversity was analyzed using 16s ... | 2009 | 19796138 |
| role of a novel disulfide bridge within the all-beta fold of soluble rieske proteins. | rieske proteins and rieske ferredoxins are present in the three domains of life and are involved in a variety of cellular processes. despite their functional diversity, these small fe-s proteins contain a highly conserved all-beta fold, which harbors a [2fe-2s] rieske center. we have identified a novel subtype of rieske ferredoxins present in hyperthermophilic archaea, in which a two-cysteine conserved sktpcx((2-3))c motif is found at the c-terminus. we establish that in the acidianus ambivalens ... | 2010 | 19862563 |
| acidianus filamentous virus 1 coat proteins display a helical fold spanning the filamentous archaeal viruses lineage. | acidianus filamentous virus 1 (afv1), a member of the lipothrixviridae family, infects the hyperthermophilic, acidophilic crenarchaeaon acidianus hospitalis. the virion, covered with a lipidic outer shell, is 9,100-a long and contains a 20.8-kb linear dsdna genome. we have identified the two major coat proteins of the virion (mcps; 132 and 140 amino acids). they bind dna and form filaments when incubated with linear dsdna. a c-terminal domain is identified in their crystal structure with a four- ... | 2009 | 19934032 |
| biogenic scorodite crystallization by acidianus sulfidivorans for arsenic removal. | scorodite is an arsenic mineral with the chemical formula feaso(4)*2h(2)o. it is the most common natural arsenate associated with arsenic-bearing ore deposits. in the present study we show that the thermoacidophilic iron-oxidizing archaeon acidianus sulfidivorans is able to precipitate scorodite in the absence of any primary minerals or seed crystals, when grown on 0.7 g l(-1) ferrous iron (fe(2+)) at 80 degrees c and ph 1 in the presence of 1.9 g l(-1) arsenate (h(3)aso(4)). the simultaneous bi ... | 2010 | 20017476 |
| getting the best out of long-wavelength x-rays: de novo chlorine/sulfur sad phasing of a structural protein from atv. | the structure of a 14 kda structural protein from acidianus two-tailed virus (atv) was solved by single-wavelength anomalous diffraction (sad) phasing using x-ray data collected at 2.0 a wavelength. although the anomalous signal from methionine sulfurs was expected to suffice to solve the structure, one chloride ion turned out to be essential to achieve phasing. the minimal data requirements and the relative contributions of the cl and s atoms to phasing are discussed. this work supports the fea ... | 2010 | 20179342 |
| orf157 from the archaeal virus acidianus filamentous virus 1 defines a new class of nuclease. | acidianus filamentous virus 1 (afv1) (lipothrixviridae) is an enveloped filamentous virus that was characterized from a crenarchaeal host. it infects acidianus species that thrive in the acidic hot springs (>85 degrees c and ph <3) of yellowstone national park, wy. the afv1 20.8-kb, linear, double-stranded dna genome encodes 40 putative open reading frames whose sequences generally show little similarity to other genes in the sequence databases. because three-dimensional structures are more cons ... | 2010 | 20200253 |
| crystal structure of group ii chaperonin in the open state. | thermosomes are group ii chaperonins responsible for protein refolding in an atp-dependent manner. little is known regarding the conformational changes of thermosomes during their functional cycle due to a lack of high-resolution structure in the open state. here, we report the first complete crystal structure of thermosome (ratcpnβ) in the open state from acidianus tengchongensis. there is a ∼30° rotation of the apical and lid domains compared with the previous closed structure. besides, the st ... | 2010 | 20947016 |
| sulfur oxidation activities of pure and mixed thermophiles and sulfur speciation in bioleaching of chalcopyrite. | the sulfur oxidation activities of four pure thermophilic archaea acidianus brierleyi (jcm 8954), metallosphaera sedula (yn 23), acidianus manzaensis (yn 25) and sulfolobus metallicus (yn 24) and their mixture in bioleaching chalcopyrite were compared. meanwhile, the relevant surface sulfur speciation of chalcopyrite leached with the mixed thermophilic archaea was investigated. the results showed that the mixed culture, with contributing significantly to the raising of leaching rate and accelera ... | 2010 | 21194927 |
| microbial diversity in nonsulfur, sulfur and iron geothermal steam vents. | fumaroles, commonly called steam vents, are ubiquitous features of geothermal habitats. recent studies have discovered microorganisms in condensed fumarole steam, but fumarole deposits have proven refractory to dna isolation. in this study, we report the development of novel dna isolation approaches for fumarole deposit microbial community analysis. deposit samples were collected from steam vents and caves in hawaii volcanoes national park, yellowstone national park and lassen volcanic national ... | 2011 | 21223339 |
| substrate pathways and mechanisms of inhibition in the sulfur oxygenase reductase of acidianus ambivalens. | background: the sulfur oxygenase reductase (sor) is the initial enzyme of the sulfur oxidation pathway in the thermoacidophilic archaeon acidianus ambivalens. the sor catalyzes an oxygen-dependent sulfur disproportionation to h(2)s, sulfite and thiosulfate. the spherical, hollow, cytoplasmic enzyme is composed of 24 identical subunits with an active site pocket each comprising a mononuclear non-heme iron site and a cysteine persulfide. substrate access and product exit occur via apolar chimney-l ... | 2011 | 21747782 |
| Evolution of a new enzyme for carbon disulphide conversion by an acidothermophilic archaeon. | Extremophilic organisms require specialized enzymes for their exotic metabolisms. Acid-loving thermophilic Archaea that live in the mudpots of volcanic solfataras obtain their energy from reduced sulphur compounds such as hydrogen sulphide (H(2)S) and carbon disulphide (CS(2)). The oxidation of these compounds into sulphuric acid creates the extremely acidic environment that characterizes solfataras. The hyperthermophilic Acidianus strain A1-3, which was isolated from the fumarolic, ancient saun ... | 2011 | 22012399 |