1y9l
From Proteopedia
The X-ray structure of an secretion system protein
Structural highlights
FunctionSCTG_SHIFL Involved in the synthesis of the type III secretion system (T3SS), also called injectisome, which is used to inject bacterial effector proteins into eukaryotic host cells (PubMed:10085046, PubMed:11717255). Pilot protein that is required for the proper localization of the secretin MxiD/SctC in the outer membrane (PubMed:11717255). Also influences both MxiD/SctC multimerization and stability (PubMed:11717255). Required for both Ipa translocation and tissue culture cell invasion (PubMed:10085046). Binds lipids (PubMed:15775974).[1] [2] [3] Publication Abstract from PubMedThe ability to translocate virulence proteins into host cells through a type III secretion apparatus (TTSS) is a hallmark of several Gram-negative pathogens including Shigella, Salmonella, Yersinia, Pseudomonas, and enteropathogenic Escherichia coli. In common with other types of bacterial secretion apparatus, the assembly of the TTSS complex requires the preceding formation of its integral outer membrane secretin ring component. We have determined at 1.5 A the structure of MxiM28-142, the Shigella pilot protein that is essential for the assembly and membrane association of the Shigella secretin, MxiD. This represents the first atomic structure of a secretin pilot protein from the several bacterial secretion systems containing an orthologous secretin component. A deep hydrophobic cavity is observed in the novel 'cracked barrel' structure of MxiM, providing a specific binding domain for the acyl chains of bacterial lipids, a proposal that is supported by our various lipid/MxiM complex structures. Isothermal titration analysis shows that the C-terminal domain of the secretin, MxiD525-570, hinders lipid binding to MxiM. Structure and biochemical analysis of a secretin pilot protein.,Lario PI, Pfuetzner RA, Frey EA, Creagh L, Haynes C, Maurelli AT, Strynadka NC EMBO J. 2005 Mar 23;24(6):1111-21. Epub 2005 Mar 10. PMID:15775974[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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