title: Crystal structure of the passenger domain of the Escherichia coli autotransporter EspP.
abstract: Autotransporters represent a large superfamily of known and putative virulence factors produced by Gram-negative bacteria. They consist of an N-terminal "passenger domain" responsible for the specific effector functions of the molecule and a C-terminal "β-domain" responsible for translocation of the passenger across the bacterial outer membrane. Here, we present the 2.5-Å crystal structure of the passenger domain of the extracellular serine protease EspP, produced by the pathogen Escherichia coli O157:H7 and a member of the serine protease autotransporters of Enterobacteriaceae (SPATEs). Like the previously structurally characterized SPATE passenger domains, the EspP passenger domain contains an extended right-handed parallel β-helix preceded by an N-terminal globular domain housing the catalytic function of the protease. Of note, however, is the absence of a second globular domain protruding from this β-helix. We describe the structure of the EspP passenger domain in the context of previous results and provide an alternative hypothesis for the function of the β-helix within SPATEs.
authors.affiliation: Campbell Family Cancer Research Institute, Ontario Cancer Institute, University Health Network, Toronto Medical Discovery Tower, Toronto, Ontario, Canada M5G 1L7.
authors.forename: Shekeb
authors.initials: S
authors.lastname: Khan
authors.forename: Hira S
authors.initials: HS
authors.lastname: Mian
authors.forename: Linda E
authors.initials: LE
authors.lastname: Sandercock
authors.forename: Nickolay Y
authors.initials: NY
authors.lastname: Chirgadze
authors.forename: Emil F
authors.initials: EF
authors.lastname: Pai
mesh_terms: D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008956:Models, Chemical; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; C107189:EspP protein, E coli; D012697:Serine Endopeptidases