2vt1 | pdb_00002vt1

Crystal structure of the cytoplasmic domain of Spa40, the specificity switch for the Shigella flexneri Type III Secretion System

spinqualitylabelsall models 2vt1, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2vt1 is a 2 chain structure with sequence from Shigella flexneri. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SPAS_SHIFL Required for surface presentation of invasion plasmid antigens. Could play a role in preserving the translocation competence of the ipa antigens. Required for invasion and for secretion of the three ipa proteins. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The pathogenic bacterium Shigella flexneri uses a type III secretion system to inject virulence factors from the bacterial cytosol directly into host cells. The machinery that identifies secretion substrates and controls the export of extracellular components and effector proteins consists of several inner-membrane and cytoplasmic proteins. One of the inner membrane components, Spa40, belongs to a family of proteins proposed to regulate the switching of substrate specificity of the export apparatus. We show that Spa40 is cleaved within the strictly conserved amino acid sequence NPTH and substitution of the proposed autocatalytic residue abolishes cleavage. Here we also report the crystal structure of the cytoplasmic complex Spa40(C) and compare it with the recent structures of the homologues from Escherichia coli and Salmonella typhimurium. These structures reveal the tight association of the cleaved fragments and show that the conserved NPTH sequence lies on a loop which, when cleaved, swings away from the catalytic N257 residue, resulting in different surface features in this region. This structural rearrangement suggests a mechanism by which non-cleaving forms of these proteins interfere with correct substrate switching of the apparatus. Crystal structure of Spa40, the specificity switch for the Shigella flexneri type III secretion system.,Deane JE, Graham SC, Mitchell EP, Flot D, Johnson S, Lea SM Mol Microbiol. 2008 Jul;69(1):267-76. Epub 2008 May 15. PMID:18485071 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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