(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Proteobacteria: NE > Gammaproteobacteria: NE > Xanthomonadales: NE > Xanthomonadaceae: NE > Xanthomonas: NE > Xanthomonas campestris: NE
Warning: This entry is a compilation of different species or line or strain with more than 90% amino acide identity. You can retrieve all strain data
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) Xanthomonas campestris: N, E.
Xanthomonas campestris pv. campestris: N, E.
Xanthomonas campestris pv. musacearum NCPPB 2005: N, E.
Xanthomonas campestris pv. campestris str. 8004: N, E.
Xanthomonas campestris pv. campestris str. B100: N, E.
Xanthomonas campestris pv. campestris str. ATCC 33913: N, E.
Xanthomonas campestris pv. raphani 756C: N, E.
Xanthomonas campestris pv. viticola: N, E.
Xanthomonas campestris pv. musacearum NCPPB 4379: N, E.
Xanthomonas campestris pv. musacearum NCPPB 4380: N, E.
Xanthomonas campestris pv. musacearum NCPPB 4392: N, E.
Xanthomonas campestris pv. musacearum NCPPB 4394: N, E.
Xanthomonas campestris pv. musacearum NCPPB 4384: N, E.
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MTYPGYSFTPKRLDVRPGIAMSYLDEGPRDGEVVVMLHGNPSWSYLWRHL VSGLSDRYRCIVPDHIGMGLSDKPDDAPDAQPRYDYTLQSRVDDLDRLLQ HLGITGPITLAVHDWGGMIGFGWALSHHEQVKRLVITNTAAFPLPPEKPM PWQIAMGRHWRLGEWFIRTFNAFSSGASWLGVSRRMPAAVRRAYVAPYDS WKNRISTIRFMQDIPLSPADQAWSLLERSAQALPSFAGRPAFIAWGLRDI CFDKHFLAGFRRALPQAEVMAFDDANHYVLEDKHEVLVPAIRAFLERNPL
OleB is an alpha/beta-hydrolase found in bacteria that biosynthesize long-chain olefinic hydrocarbons, but its function has remained obscure. We report that OleB from the Gram-negative bacterium Xanthomonas campestris performs an unprecedented beta-lactone decarboxylation reaction, to complete cis-olefin biosynthesis. OleB reactions monitored by (1)H nuclear magnetic resonance spectroscopy revealed a selectivity for decarboxylating cis-beta-lactones and no discernible activity with trans-beta-lactones, consistent with the known configuration of pathway intermediates. Protein sequence analyses showed OleB proteins were most related to haloalkane dehalogenases (HLDs) and retained the canonical Asp-His-Asp catalytic triad of HLDs. Unexpectedly, it was determined that an understudied subfamily, denoted as HLD-III, is comprised mostly of OleB proteins encoded within oleABCD gene clusters, suggesting a misannotation. OleB from X. campestris showed very low dehalogenase activity only against haloalkane substrates with long alkyl chains. A haloalkane substrate mimic alkylated wild-type X. campestris OleB but not OleBD114A, implicating this residue as the active site nucleophile as in HLDs. A sequence-divergent OleB, found as part of a natural OleBC fusion and classified as an HLD-III, from the Gram-positive bacterium Micrococcus luteus was demonstrated to have the same activity, stereochemical preference, and dependence on the proposed Asp nucleophile. H2(18)O studies with M. luteus OleBC suggested that the canonical alkyl-enzyme intermediate of HLDs is hydrolyzed differently by OleB enzymes, as (18)O is not incorporated into the nucleophilic aspartic acid. This work defines a previously unrecognized reaction in nature, functionally identifies some HLD-III enzymes as beta-lactone decarboxylases, and posits an enzymatic mechanism of beta-lactone decarboxylation.
The genus Xanthomonas is a diverse and economically important group of bacterial phytopathogens, belonging to the gamma-subdivision of the Proteobacteria. Xanthomonas axonopodis pv. citri (Xac) causes citrus canker, which affects most commercial citrus cultivars, resulting in significant losses worldwide. Symptoms include canker lesions, leading to abscission of fruit and leaves and general tree decline. Xanthomonas campestris pv. campestris (Xcc) causes black rot, which affects crucifers such as Brassica and Arabidopsis. Symptoms include marginal leaf chlorosis and darkening of vascular tissue, accompanied by extensive wilting and necrosis. Xanthomonas campestris pv. campestris is grown commercially to produce the exopolysaccharide xanthan gum, which is used as a viscosifying and stabilizing agent in many industries. Here we report and compare the complete genome sequences of Xac and Xcc. Their distinct disease phenotypes and host ranges belie a high degree of similarity at the genomic level. More than 80% of genes are shared, and gene order is conserved along most of their respective chromosomes. We identified several groups of strain-specific genes, and on the basis of these groups we propose mechanisms that may explain the differing host specificities and pathogenic processes.
Xanthomonas campestris (pv. campestris) hypothetical protein xcc1541