title: Structural analysis of SepL, an enteropathogenic Escherichia coli type III secretion-system gatekeeper protein.
abstract: During infection, enteropathogenic Escherichia coli assembles a complex multi-protein type III secretion system that traverses the bacterial membranes and targets the host cell membrane to directly deliver virulence or effector proteins to the host cytoplasm. As this secretion system is composed of more than 20 proteins, many of which form oligomeric associations, its assembly must be tightly regulated. A protein called the gatekeeper, or SepL, ensures that the secretion of the translocon component, which inserts into the host membrane, occurs before the secretion of effectors. The crystal structure of the gatekeeper SepL was determined and compared with the structures of SepL homologues from other bacterial pathogens in order to identify SepL residues that may be critical for its role in type III secretion-system assembly.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Brianne J
authors.initials: BJ
authors.lastname: Burkinshaw
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Souza
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Natalie C J
authors.initials: NC
authors.lastname: Strynadka
mesh_terms: D000595:Amino Acid Sequence; D058947:Bacterial Secretion Systems; D003460:Crystallization; D018360:Crystallography, X-Ray; D054308:Enteropathogenic Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012996:Solutions; D040681:Structural Homology, Protein
chemical_list: D058947:Bacterial Secretion Systems; D029968:Escherichia coli Proteins; C416081:SepL protein, E coli; D012996:Solutions
keywords: bacterial pathogenesis; protein secretion