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-Structure paper
Title | Use of chimeric type IV secretion systems to define contributions of outer membrane subassemblies for contact-dependent translocation. |
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Journal, issue, pages | Mol Microbiol, Vol. 105, Issue 2, Page 273-293, Year 2017 |
Publish date | May 18, 2017 |
Authors | Jay E Gordon / Tiago R D Costa / Roosheel S Patel / Christian Gonzalez-Rivera / Mayukh K Sarkar / Elena V Orlova / Gabriel Waksman / Peter J Christie / |
PubMed Abstract | Recent studies have shown that conjugation systems of Gram-negative bacteria are composed of distinct inner and outer membrane core complexes (IMCs and OMCCs, respectively). Here, we characterized ...Recent studies have shown that conjugation systems of Gram-negative bacteria are composed of distinct inner and outer membrane core complexes (IMCs and OMCCs, respectively). Here, we characterized the OMCC by focusing first on a cap domain that forms a channel across the outer membrane. Strikingly, the OMCC caps of the Escherichia coli pKM101 Tra and Agrobacterium tumefaciens VirB/VirD4 systems are completely dispensable for substrate transfer, but required for formation of conjugative pili. The pKM101 OMCC cap and extended pilus also are dispensable for activation of a Pseudomonas aeruginosa type VI secretion system (T6SS). Chimeric conjugation systems composed of the IMC joined to OMCCs from the A. tumefaciens VirB/VirD4, E. coli R388 Trw, and Bordetella pertussis Ptl systems support conjugative DNA transfer in E. coli and trigger P. aeruginosa T6SS killing, but not pilus production. The A. tumefaciens VirB/VirD4 OMCC, solved by transmission electron microscopy, adopts a cage structure similar to the pKM101 OMCC. The findings establish that OMCCs are highly structurally and functionally conserved - but also intrinsically conformationally flexible - scaffolds for translocation channels. Furthermore, the OMCC cap and a pilus tip protein coregulate pilus extension but are not required for channel assembly or function. |
External links | Mol Microbiol / PubMed:28452085 / PubMed Central |
Methods | EM (single particle) |
Resolution | 21.0 Å |
Structure data | EMDB-3725: |
Source |
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