Genetic analysis of the colicin V secretion pathway.

Zhang, Li Hong; Fath, Michael; Mahanty, H. K.; Tai, Phang C.; Kolter, Roberto

doi:10.1093/genetics/141.1.25

Cited by 69 publications

(18 citation statements)

References 26 publications

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“…Interestingly, antibacterial activity was completely abolished upon alanine replacement of the two cysteines involved in the MccV disulfide bond. 46 This indicates that, as with MccJ25, folding of MccV is required for antibacterial activity. Similar to MccV, lysates from bacteria only harbouring MccL structural (mclL) and self-immunity genes (mclI) were found to possess antibacterial activity, 39 suggesting that unprocessed MccL is active.…”

Section: Antibacterial Activity Of Promicrocinsmentioning

confidence: 96%

Microcins, gene-encoded antibacterial peptides from enterobacteria

et al. 2007

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Microcins are gene-encoded antibacterial peptides, with molecular masses below 10 kDa, produced by enterobacteria. They are secreted under conditions of nutrient depletion and exert potent antibacterial activity against closely related species. Typical gene clusters encoding the microcin precursor, the self-immunity factor, the secretion proteins and frequently the post-translational modification enzymes are located either on plasmids or on the chromosome. In contrast to most of the antibiotics of microbial origin, which are non-ribosomally synthesized by multimodular enzymes termed peptide synthetases, microcins are ribosomally synthesized as precursors, which are further modified enzymatically. They form a restricted class of potent antibacterial peptides. Fourteen microcins have been reported so far, among which only seven have been isolated and characterized. Despite the low number of known representatives, microcins exhibit a diversity of structures and antibacterial mechanisms. This review provides an updated overview of microcin structures, antibacterial activities, genetic systems and biosyntheses, as well as of their mechanisms of action.

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Section: Antibacterial Activity Of Promicrocinsmentioning

confidence: 96%

Microcins, gene-encoded antibacterial peptides from enterobacteria

et al. 2007

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“…Colicin V (ColV), 1 an antibacterial toxin produced by Enterobacteriaciae, kills sensitive target cells by disrupting their cell membrane potential (1). In the Gram-negative bacterium Escherichia coli, ColV is secreted by a dedicated type I exporter system across both the cytoplamic and outer membranes directly into the environment outside the cells.…”

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confidence: 99%

Molecular Basis for Differential Nucleotide Binding of the Nucleotide-Binding Domain of ABC-Transporter CvaB

et al. 2006

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The cytoplasmic membrane protein CvaB, involved in colicin V secretion in Escherichia coli, belongs to the ABC transporter family in which ATP hydrolysis is typically the driving force for substrate transport. However, our previous studies indicated that the nucleotide-binding domain of CvaB could also bind and hydrolyze GTP, and indeed highly preferred GTP over ATP at low temperatures. In this study, we have examined the molecular basis of this preference. Sequence alignment and homology modeling of the CvaB nucleotide binding domain predicted that the aromatic stacking region of CvaB (Y 501 DSQ-loop) had a role in the differential binding of nucleotides, and the Ser503 and Gln504 provided potential hydrogen-bonds to GTP but not to ATP. Site-directed mutagenesis of the Y 501 DSQ-loop: mutations S503A, Q504L, and double mutation S503A/Q504L, was made to test the predicted hydrogen-bonds with GTP. The double mutation S503A/Q504L increased the affinity for ATP by 6-fold, whereas the affinity for GTP was reduced slightly: the ATP/GTP-binding ratio increased about 10-fold. The temperature-effect assays on nucleotide binding and hydrolysis further indicated that the double-mutant protein had largely eliminated the difference to substrate ATP and GTP and behaved more closely to the NBD of typical ABC transporter HlyB. Therefore, we conclude that the Ser 503 and Gln 504 in aromatic stacking region of CvaB block the ATP binding and are important for the GTP-binding preference. *To whom correspondence should be addressed: Phone, 404-651-3109; fax, 404-651-2509; e-mail, biopct@langate.gsu.edu. NIH Public Access Author ManuscriptBiochemistry. Author manuscript; available in PMC 2008 August 13. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptEscherichia coli, ColV is secreted by a dedicated type-I exporter system across both the cytoplamic and outer membranes directly into the environment outside the cells. At least three protein components participate in the ColV export system: two plasmid-born proteins CvaA and CvaB in the cytoplasmic membrane and a host chromosomal gene product TolC in the outer membrane (2,3).The cytoplasmic membrane protein CvaB plays pivotal roles in the ColV export system. CvaB belongs to the family of ATP-binding cassette transporters (4,5), like the α-hemolysin exporter HlyB (6), the Cystic Fibrosis trans-membrane conductance regulator (7), and the multidrug resistance P-glycoprotein (8). The N-terminal proteolytic domain of CvaB processes the leader region of ColV precursor at the double-glycine site (9-11), the trans-membrane domains in the middle of CvaB form the cytoplasmic channel (3,9,12), and the C-terminal nucleotide-binding domain supplies energy for ColV secretion. Although the sequence of the proteolytic Nterminal domain of CvaB is unique among ABC transporters (11), the C-terminal nucleotide binding domain (NBD) retains a high level of homology with other family members (4,5,13). Several highly conserved ABC-NBD motifs are found in the CvaB sequence, su...

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“…Both closed ST-reference EH41 and 4 strains are colicinogenic and code for colicins E2 and E1, respectively encoded on relative small plasmids [143] (). Strain 4 further carries a 65 782 bp colicin V plasmid pColV-4 [145]. BLASTn of its sequence [111, 142] against the non-redundant (nr) NCBI database revealed local similarity to O113:H21 plasmid pRM10466-2 () and other phylogenetically diverse E.…”

Section: Resultsmentioning

confidence: 99%

“…3). Strain 4 further carries a 65 782 bp colicin V plasmid pColV-4 [145]. BLASTn of its sequence [111,142] against the non-redundant (nr) NCBI database revealed local similarity to O113:H21 plasmid pRM10466-2 (Fig.…”

Section: Comprehensive Analyses Of Pathochromosome Architectures Phag...mentioning

confidence: 99%

Pathogenomes and variations in Shiga toxin production among geographically distinct clones of Escherichia coli O113:H21

et al. 2022

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Infections with globally disseminated Shiga toxin-producing Escherichia coli (STEC) of the O113:H21 serotype can progress to severe clinical complications, such as hemolytic uremic syndrome (HUS). Two phylogeographically distinct clonal complexes have been established by multi locus sequence typing (MLST). Infections with ST-820 isolates circulating exclusively in Australia have caused severe human disease, such as HUS. Conversely, ST-223 isolates prevalent in the US and outside Australia seem to rarely cause severe human disease but are frequent contaminants. Following a genomic epidemiology approach, we wanted to gain insights into the underlying cause for this disparity. We examined the plasticity in the genome make-up and Shiga toxin production in a collection of 20 ST-820 and ST-223 strains isolated from produce, the bovine reservoir, and clinical cases. STEC are notorious for assembly into fragmented draft sequences when using short-read sequencing technologies due to the extensive and partly homologous phage complement. The application of long-read technology (LRT) sequencing yielded closed reference chromosomes and plasmids for two representative ST-820 and ST-223 strains. The established high-resolution framework, based on whole genome alignments, single nucleotide polymorphism (SNP)-typing and MLST, includes the chromosomes and plasmids of other publicly available O113:H21 sequences and allowed us to refine the phylogeographical boundaries of ST-820 and ST-223 complex isolates and to further identify a historic non-shigatoxigenic strain from Mexico as a quasi-intermediate. Plasmid comparison revealed strong correlations between the strains’ featured pO113 plasmid genotypes and chromosomally inferred ST, which suggests coevolution of the chromosome and virulence plasmids. Our pathogenicity assessment revealed statistically significant differences in the Stx2a-production capabilities of ST-820 as compared to ST-223 strains under RecA-induced Stx phage mobilization, a condition that mimics Stx-phage induction. These observations suggest that ST-820 strains may confer an increased pathogenic potential in line with the strain-associated epidemiological metadata. Still, some of the tested ST-223 cultures sourced from contaminated produce or the bovine reservoir also produced Stx at levels comparable to those of ST-820 isolates, which calls for awareness and for continued surveillance of this lineage.

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Genetic analysis of the colicin V secretion pathway.

Cited by 69 publications

References 26 publications

Microcins, gene-encoded antibacterial peptides from enterobacteria

Microcins, gene-encoded antibacterial peptides from enterobacteria

Molecular Basis for Differential Nucleotide Binding of the Nucleotide-Binding Domain of ABC-Transporter CvaB

Pathogenomes and variations in Shiga toxin production among geographically distinct clones of Escherichia coli O113:H21

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