title: Structure of the Yersinia type III secretory system chaperone SycE.
abstract: In the type III secretory system of bacterial pathogens, a large number of sequence-divergent but characteristically small (approximately 14-19 kDa), acidic (pI approximately 4-5) chaperone proteins have been identified. We present the 1.74 A resolution crystal structure of the Yersinia pseudotuberculosis chaperone SycE, whose action in promoting translocation of YopE into host macrophages is essential to Yersinia pathogenesis. SycE, a compact, globular dimer with a novel fold, has two large hydrophobic surface patches that may form binding sites for YopE or other type III components. These patches are formed by structurally key residues that are conserved among many chaperones, suggesting shared structural and functional relationships. A negative electrostatic potential covers almost the entire surface of SycE and is likely conserved in character, but not in detail, among chaperones. The structure provides the first structural insights into possible modes of action of SycE and type III chaperones in general.
authors.affiliation: Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093-0314, USA.
authors.forename: S
authors.initials: S
authors.lastname: Birtalan
authors.forename: P
authors.initials: P
authors.lastname: Ghosh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019281:Dimerization; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D055672:Static Electricity; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism*; D015011:Yersinia pseudotuberculosis / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; C081269:SycE protein, Yersinia; D015534:Trans-Activators