5H6I
Crystal Structure of GBS CAMP Factor
Summary for 5H6I
| Entry DOI | 10.2210/pdb5h6i/pdb |
| Descriptor | Protein B, SULFATE ION, CHLORIDE ION, ... (4 entities in total) |
| Functional Keywords | pore forming toxin, toxin |
| Biological source | Streptococcus agalactiae |
| Total number of polymer chains | 3 |
| Total formula weight | 81436.14 |
| Authors | Jin, T.C.,Brefo-Mensah, E.K. (deposition date: 2016-11-13, release date: 2017-11-22, Last modification date: 2024-03-20) |
| Primary citation | Jin, T.,Brefo-Mensah, E.,Fan, W.,Zeng, W.,Li, Y.,Zhang, Y.,Palmer, M. Crystal structure of theStreptococcus agalactiaeCAMP factor provides insights into its membrane-permeabilizing activity. J.Biol.Chem., 293:11867-11877, 2018 Cited by PubMed Abstract: is an important human opportunistic pathogen that can cause serious health problems, particularly among newborns and older individuals. contains the CAMP factor, a pore-forming toxin first identified in this bacterium. The CAMP reaction is based on the co-hemolytic activity of the CAMP factor and is commonly used to identify in the clinic. Closely related proteins are present also in other Gram-positive pathogens. Although the CAMP toxin was discovered more than a half century ago, no structure from this toxin family has been reported, and the mechanism of action of this toxin remains unclear. Here, we report the first structure of this toxin family, revealing a structural fold composed of 5 + 3-helix bundles. Further analysis by protein truncation and site-directed mutagenesis indicated that the N-terminal 5-helix bundle is responsible for membrane permeabilization, whereas the C-terminal 3-helix bundle is likely responsible for host receptor binding. Interestingly, the C-terminal domain inhibited the activity of both full-length toxin and its N-terminal domain. Moreover, we observed that the linker region is highly conserved and has a conserved DLDAT sequence motif. Structurally, this linker region extensively interacted with both terminal CAMP factor domains, and mutagenesis disclosed that the conserved sequence motif is required for CAMP factor's co-hemolytic activity. In conclusion, our results reveal a unique structure of this bacterial toxin and help clarify the molecular mechanism of its co-hemolytic activity. PubMed: 29884770DOI: 10.1074/jbc.RA118.002336 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.45 Å) |
Structure validation
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