title: Structure of TonB in complex with FhuA, E. coli outer membrane receptor.
abstract: The cytoplasmic membrane protein TonB spans the periplasm of the Gram-negative bacterial cell envelope, contacts cognate outer membrane receptors, and facilitates siderophore transport. The outer membrane receptor FhuA from Escherichia coli mediates TonB-dependent import of ferrichrome. We report the 3.3 angstrom resolution crystal structure of the TonB carboxyl-terminal domain in complex with FhuA. TonB contacts stabilize FhuA's amino-terminal residues, including those of the consensus Ton box sequence that form an interprotein beta sheet with TonB through strand exchange. The highly conserved TonB residue arginine-166 is oriented to form multiple contacts with the FhuA cork, the globular domain enclosed by the beta barrel.
authors.affiliation: Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, Quebec, H3A 2B4, Canada.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Pawelek
authors.forename: Nathalie
authors.initials: N
authors.lastname: Croteau
authors.forename: Christopher
authors.initials: C
authors.lastname: Ng-Thow-Hing
authors.forename: Cezar M
authors.initials: CM
authors.lastname: Khursigara
authors.forename: Natalia
authors.initials: N
authors.lastname: Moiseeva
authors.forename: Marc
authors.initials: M
authors.lastname: Allaire
authors.forename: James W
authors.initials: JW
authors.lastname: Coulton
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D005290:Ferric Compounds; C050900:FhuA protein, E coli; D008565:Membrane Proteins; C489181:tonB protein, E coli