| biosynthesis of iso-fatty acids in myxobacteria. | the fatty acid (fa) profiles of the myxobacteria stigmatella aurantiaca and myxococcus xanthus were investigated by acidic methanolysis of total cell extracts and gc or gc-ms analysis. the main components were 13-methyltetradecanoic acid (iso-15:0) and (z)-hexadec-11-enoic acid (16:1, omega-5 cis). the biosynthesis of iso-fas was investigated in several feeding experiments. feeding of isovaleric acid (iva) to a mutant impaired in the degradation of leucine to isovaleryl-coa (iv-coa)(bkd mutant) ... | 2005 | 16032360 |
| biosynthesis and identification of volatiles released by the myxobacterium stigmatella aurantiaca. | the volatiles released by agar plate cultures of two strains of the myxobacterium stigmatella aurantiaca (strains sg a15 and dw4/3-1) were collected in a closed-loop stripping apparatus (clsa) and analyzed by gc-ms. large numbers of substances from different compound classes (ketones, esters, lactones, terpenes, and sulfur and nitrogen compounds) were identified; several of them are reported from natural sources for the first time. the volatiles 2-methyltridecan-4-one (17), its isomer 3-methyltr ... | 2005 | 16208730 |
| myxobacters from arid mexican soil. | myxobacters were found to be common inhabitants of the arid soils from the monterrey, nuevo leon, mexico, area. thirteen species of the genera myxococcus, archangium, cystobacter, stigmatella, polyangium, and chondromyces were isolated on a mineral salts agar supplemented with bakers' yeast and filter paper. greater species diversity per soil sample was found in the region receiving 400 to 800 mm of annual rainfall as compared with soils from an area having only 200 to 400 mm of rainfall. | 1976 | 16345178 |
| integration into the phage attachment site, attb, impairs multicellular differentiation in stigmatella aurantiaca. | stigmatella aurantiaca displays a complex developmental life cycle in response to starvation conditions that results in the formation of tree-like fruiting bodies capable of producing spores. the phage mx8, first isolated from the close relative myxococcus xanthus, is unable to infect s. aurantiaca cells and integrate into the genome. however, plasmids containing mx8 fragments encoding the integrase and attp are able to integrate at the attb locus in the s. aurantiaca genome by site-specific rec ... | 2006 | 16484181 |
| nonribosomal peptide biosynthesis: point mutations and module skipping lead to chemical diversity. | | 2006 | 16506259 |
| a unique mechanism for methyl ester formation via an amide intermediate found in myxobacteria. | secondary metabolism involves a broad diversity of biochemical reactions that result in a wide variety of biologically active compounds. terminal amide formation during the biosynthesis of the myxobacterial electron-transport inhibitor, myxothiazol, was analyzed by heterologous expression of the unique nonribosomal-peptide synthetase, mtag, and incubation with a synthesized substrate mimic. these experiments provide evidence that the terminal amide is formed from a carrier protein-bound myxothia ... | 2006 | 16807964 |
| evolutionary diversity of ketoacyl synthases in cellulolytic myxobacterium sorangium. | the diversity of type i polyketide synthases (pkss) in cellulolytic myxobacterium sorangium was explored by assaying the ketoacyl synthases (kss) in 10 sorangium strains with two degenerate primer sets and 64 different ks fragments were obtained. for their deduced amino acid sequences, eight were identical to three known kss from sorangium and magnetospirillum, while the others showed 54-83% identities to the modular ks domains reported from various microorganisms. parts of the sorangium kss tig ... | 2007 | 16899349 |
| a type ii polyketide synthase from the gram-negative bacterium stigmatella aurantiaca is involved in aurachin alkaloid biosynthesis. | | 2007 | 17335090 |
| from genetic diversity to metabolic unity: studies on the biosynthesis of aurafurones and aurafuron-like structures in myxobacteria and streptomycetes. | the myxobacterial polyketide secondary metabolites aurafuron a and b were identified by genome mining in the myxobacterial strain stigmatella aurantiaca dw4/3-1. the compounds contain an unusual furanone moiety and resemble metabolites isolated from soil-dwelling and marine actinobacteria, a fungus and mollusks. we describe here the cloning and functional analysis of the aurafuron biosynthetic gene cluster, including site-directed mutagenesis and feeding studies using labeled precursors. the pol ... | 2007 | 17919655 |
| mutasynthesis-derived myxalamids and origin of the isobutyryl-coa starter unit of myxalamid b. | myxalamids are potent inhibitors of the eukaryotic electron transport chain produced by different myxobacteria. here, we describe the identification of the myxalamid biosynthesis gene cluster from myxococcus xanthus. additionally, new myxalamids (5-13) have been obtained by mutasynthesis from bkd mutants of m. xanthus and stigmatella aurantiaca. moreover, as these bkd mutants are still able to produce myxalamid b (2), the origin of the isobutyryl-coa (ib-coa) starter unit required for its biosyn ... | 2007 | 17955482 |
| dkxanthene biosynthesis--understanding the basis for diversity-oriented synthesis in myxobacterial secondary metabolism. | the dkxanthenes are a family of yellow pigments which play a critical role in myxobacterial development. thirteen unique structures from myxococcus xanthus dk1622 differ in the length of their characteristic polyene functionality, as well as the extent of methyl branching. we aimed to understand the mechanistic basis for this "molecular promiscuity" by analyzing the gene cluster in dk1622, and comparing it to the dkxanthene biosynthetic locus in a second myxobacterium, stigmatella aurantiaca dw4 ... | 2008 | 18721748 |
| myxochromide b3, a new member of the myxochromide family of secondary metabolites. | myxochromides are cyclic depsipeptides with an unsaturated polyketide side chain, which have been reported from different myxobacterial species, e.g., myxococcus xanthus and stigmatella aurantiaca. to date, myxochromides are subdivided into the groups a and s, according to their peptidic core structure. the peptide moiety of the new myxochromide b3 (1), which was isolated from a myxobacterial strain of the genus myxococcus, differs from that of myxochromides a and s. compound 1 thus is the first ... | 2008 | 18803421 |
| eukaryotic-like protein kinases in the prokaryotes and the myxobacterial kinome. | ser/thr/tyr kinases, which together comprise a major class of regulatory proteins in eukaryotes, were not believed to play an important role in prokaryotes until recently. however, our analysis of 626 prokaryotic genomes reveals that eukaryotic-like protein kinases (elks) are found in nearly two-thirds of the sequenced strains. we have identified 2697 elks, most of which are encoded by multicellular strains of the phyla proteobacteria (myxococcales), actinobacteria, cyanobacteria, and chloroflex ... | 2008 | 18836084 |
| biosynthesis of aurachins a-l in stigmatella aurantiaca: a feeding study. | the isolation of aurachins a-l (1-11) from stigmatella aurantiaca strain sg a15 is described. their structures and relative configurations were deduced from spectroscopic data, in particular nmr. three structural types were identified: a-type aurachins (1, 2, 6) are c-3 oxygen-substituted quinolines carrying a farnesyl residue on c-4, c-type aurachins (3, 4, 7-11) are c-4 oxygen-substituted quinolines carrying a farnesyl residue on c-3, and c-type aurachin e (5) has a [1,1a,8,d]imidazoloquinolin ... | 2008 | 18989924 |
| a quinoline antibiotic from rhodococcus erythropolis jcm 6824. | a new quinoline antibiotic, aurachin re, was isolated and identified from a culture broth of rhodococcus erythropolis jcm 6824. the aurachin re structure was determined based on nmr and mass spectrometric analysis. the structure is similar to that of aurachin c antibiotics that have been identified from stigmatella aurantiaca. compared to aurachin c, however, aurachin re exhibits a wide and strong antimicrobial spectrum against both high- and low-gc gram-positive bacteria. | 2008 | 19168983 |
| phylogenetic analysis of the triterpene cyclase protein family in prokaryotes and eukaryotes suggests bidirectional lateral gene transfer. | functional constraints to modifications in triterpene cyclase amino acid sequences make them good candidates for evolutionary studies on the phylogenetic relatedness of these enzymes in prokaryotes as well as in eukaryotes. in this study, we used a set of identified triterpene cyclases, a group of mainly bacterial squalene cyclases and a group of predominantly eukaryotic oxidosqualene cyclases, as seed sequences to identify 5288 putative triterpene cyclase homologues in publicly available databa ... | 2009 | 19207562 |
| auaa, a membrane-bound farnesyltransferase from stigmatella aurantiaca, catalyzes the prenylation of 2-methyl-4-hydroxyquinoline in the biosynthesis of aurachins. | aurachins are quinoline alkaloids isolated from the myxobacterium stigmatella aurantiaca. they are substituted with an isoprenoid side chain and act as potent inhibitors in the electron transport chain. a biosynthetic gene cluster that contains at least five genes (auaa-auae) has been identified for aurachin biosynthesis. in this study, auaa, the gene encoding a putative prenyltransferase of 326 amino acids, was cloned and overexpressed in escherichia coli. biochemical investigations showed that ... | 2011 | 21671333 |
| unprecedented anthranilate priming involving two enzymes of the acyl adenylating superfamily in aurachin biosynthesis. | biosynthesis of many polyketide-derived secondary metabolites is initiated by incorporating starter units other than acetate. thus, understanding their priming mechanism is of importance for metabolic engineering. insight into the loading process of anthranilate into the biosynthetic pathway for the quinoline alkaloids aurachins has been provided by the sequencing of a partial biosynthetic gene cluster in the myxobacterium stigmatella aurantiaca. the cluster encodes a predicted aryl:coa ligase a ... | 2011 | 21770425 |
| Completing the puzzle of aurachin biosynthesis in Stigmatella aurantiaca Sg a15. | The aurachins are a family of secondary metabolites, with the main members aurachin A, B, C, and D, produced by the myxobacterium Stigmatella aurantiaca Sg a15. These isoprenoid quinoline alkaloids are classified as A-type or C-type aurachins according to the position of the farnesyl residue either at C4 or C3 of the quinoline core, respectively. Previous feeding studies revealed that the C-type aurachins are converted to A-type aurachins by late stage tailoring reactions. While the core gene cl ... | 2011 | 21979787 |
| evolution of antifreeze protein genes in the diatom genus fragilariopsis: evidence for horizontal gene transfer, gene duplication and episodic diversifying selection. | hypotheses about horizontal transfer of antifreeze protein genes to ice-living diatoms were addressed using two different statistical methods available in the program prunier. the role of diversifying selection in driving the differentiation of a set of antifreeze protein genes in the diatom genus fragilariopsis was also investigated. four horizontal gene transfer events were identified. two of these took place between two major eukaryote lineages, that is from the diatom chaetoceros neogracile ... | 2011 | 22253534 |
| biosynthesis of 2-hydroxy and iso-even fatty acids is connected to sphingolipid formation in myxobacteria. | 2-hydroxy fatty acids can be found in several different organisms, including bacteria. in this study, we have studied the biosynthesis of 2-hydroxy fatty acids in the myxobacteria myxococcus xanthus and stigmatella aurantiaca, resulting in the identification of a family of stereospecific fatty acid alpha-hydroxylases. although the stereospecificities of the hydroxylases differ between these two species, they share a common function in supporting fatty acid alpha-oxidation; that is, the oxidative ... | 2009 | 19575369 |
| non-modular polyketide synthases in myxobacteria. | myxobacteria are prolific producers of a wide variety of secondary metabolites. the vast majority of these compounds are complex polyketides which are biosynthesised by multimodular polyketide synthases (pkss). in contrast, few myxobacterial metabolites isolated to date are derived from non-modular pkss, in particular type iii pkss. this review reports our progress on the characterisation of type iii pkss in myxobacteria. we also summarize current knowledge on bacterial type iii pkss, with a spe ... | 2009 | 19586645 |
| functional equivalence of hmga- and histone h1-like domains in a bacterial transcriptional factor. | histone h1 and high-mobility group a (hmga) proteins compete dynamically to modulate chromatin structure and regulate dna transactions in eukaryotes. in prokaryotes, hmga-like domains are known only in myxococcus xanthus card and its stigmatella aurantiaca ortholog. these have an n-terminal module absent in hmga that interacts with carg (a zinc-associated factor that does not bind dna) to form a stable complex essential in regulating multicellular development, light-induced carotenogenesis, and ... | 2009 | 19666574 |
| molecular and structural basis of metabolic diversity mediated by prenyldiphosphate converting enzymes. | general thermodynamic calculations using the semiempiric pm3 method have led to the conclusion that prenyldiphosphate converting enzymes require at least one divalent metal cation for the activation and cleavage of the diphosphate-prenyl ester bond, or they must provide structural elements for the efficient stabilization of the intermediate prenyl cation. the most important common structural features, which guide the product specificity in both terpene synthases and aromatic prenyl transferases ... | 2009 | 19878958 |
| insights into multienzyme docking in hybrid pks-nrps megasynthetases revealed by heterologous expression and genetic engineering. | | 2010 | 20391455 |
| comparative genomic analysis of fruiting body formation in myxococcales. | genetic programs underlying multicellular morphogenesis and cellular differentiation are most often associated with eukaryotic organisms, but examples also exist in bacteria such as the formation of multicellular, spore-filled fruiting bodies in the order myxococcales. most members of the myxococcales undergo a multicellular developmental program culminating in the formation of spore-filled fruiting bodies in response to starvation. to gain insight into the evolutionary history of fruiting body ... | 2010 | 21037205 |
| fatty acid-related phylogeny of myxobacteria as an approach to discover polyunsaturated omega-3/6 fatty acids. | in an analysis of 47 aerobic myxobacterial strains, representing 19 genera in suborders cystobacterineae, nannocystineae, sorangiineae, and a novel isolate, "aetherobacter" sbsr008, an enormously diverse array of fatty acids (fas) was found. the distribution of straight-chain fatty acids (scfas) and branched-chain fatty acids (bcfas) supports the reported clustering of strains in the phylogenetic tree based on 16s rrna genes. this finding additionally allows the prediction and assignment of the ... | 2011 | 21317327 |