title: Homology-based modeling of the Erwinia amylovora type III secretion chaperone DspF used to identify amino acids required for virulence and interaction with the effector DspE.
abstract: The structure of DspF, a type III secretion system (T3SS) chaperone required for virulence of the fruit tree pathogen Erwinia amylovora, was modeled based on predicted structural homology to characterized T3SS chaperones. This model guided the selection of 11 amino acid residues that were individually mutated to alanine via site-directed mutagenesis. Each mutant was assessed for its effect on virulence complementation, dimerization and interaction with the N-terminal chaperone-binding site of DspE. Four amino acid residues were identified that did not complement the virulence defect of a dspF knockout mutant, and three of these residues were required for interaction with the N-terminus of DspE. This study supports the significance of the predicted beta-sheet helix-binding groove in DspF chaperone function.
authors.affiliation: Department of Plant Pathology, Michigan State University, 103 Center for Integrated Plant Systems, East Lansing, MI 48824, USA.
authors.forename: Lindsay R
authors.initials: LR
authors.lastname: Triplett
authors.forename: William J
authors.initials: WJ
authors.lastname: Wedemeyer
authors.forename: George W
authors.initials: GW
authors.lastname: Sundin
mesh_terms: D000596:Amino Acids; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017124:Conserved Sequence; D044084:Erwinia amylovora / Q000737:chemistry / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D017353:Gene Deletion; D055786:Gene Knockout Techniques; D005798:Genes, Bacterial; D054884:Host-Pathogen Interactions; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010935:Plant Diseases / Q000382:microbiology; D017354:Point Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D031989:Pyrus / Q000382:microbiology; D011994:Recombinant Proteins / Q000737:chemistry; D013329:Structure-Activity Relationship; D014774:Virulence / Q000235:genetics
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; C110611:DspA protein, Erwinia amylovora; D018832:Molecular Chaperones; D011994:Recombinant Proteins