6MIC
Crystal Structure of the C-terminal half of the Vibrio cholerae minor pilin TcpB
Summary for 6MIC
| Entry DOI | 10.2210/pdb6mic/pdb |
| Descriptor | Toxin co-regulated pilus biosynthesis protein B, (4S)-2-METHYL-2,4-PENTANEDIOL, GLYCEROL, ... (4 entities in total) |
| Functional Keywords | effector domain, minor pilin, toxin co-regulated pilus, vibrio cholerae, biosynthetic protein |
| Biological source | Vibrio cholerae serotype O1 |
| Total number of polymer chains | 1 |
| Total formula weight | 19945.08 |
| Authors | Kolappan, S.,Craig, L. (deposition date: 2018-09-19, release date: 2019-08-28, Last modification date: 2024-10-23) |
| Primary citation | Gutierrez-Rodarte, M.,Kolappan, S.,Burrell, B.A.,Craig, L. TheVibrio choleraeminor pilin TcpB mediates uptake of the cholera toxin phage CTX phi. J.Biol.Chem., 294:15698-15710, 2019 Cited by PubMed Abstract: Virulent strains of the bacterial pathogen cause the diarrheal disease cholera by releasing cholera toxin into the small intestine. acquired its cholera toxin genes by lysogenic infection with the filamentous bacteriophage CTXφ. CTXφ uses its minor coat protein pIII, located in multiple copies at the phage tip, to bind to the toxin-coregulated pilus (TCP). However, the molecular details of this interaction and the mechanism of phage internalization are not well-understood. The TCP filament is a polymer of major pilins, TcpA, and one or more minor pilin, TcpB. TCP are retractile, with both retraction and assembly initiated by TcpB. Consistent with these roles in pilus dynamics, we hypothesized that TcpB controls both binding and internalization of CTXφ. To test this hypothesis, we determined the crystal structure of the C-terminal half of TcpB and characterized its interactions with CTXφ pIII. We show that TcpB is a homotrimer in its crystallographic form as well as in solution and is present in multiple copies at the pilus tip, which likely facilitates polyvalent binding to pIII proteins at the phage tip. We further show that recombinant forms of TcpB and pIII interact , and both TcpB and anti-TcpB antibodies block CTXφ infection of Finally, we show that CTXφ uptake requires TcpB-mediated retraction. Our data support a model whereby CTXφ and TCP bind in a tip-to-tip orientation, allowing the phage to be drawn into the periplasm as an extension of the pilus filament. PubMed: 31471320DOI: 10.1074/jbc.RA119.009980 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.531 Å) |
Structure validation
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