title: Evolutionary fine-tuning of conformational ensembles in FimH during host-pathogen interactions.
abstract: Positive selection in the two-domain type 1 pilus adhesin FimH enhancesEscherichia colifitness in urinary tract infection (UTI). We report a comprehensive atomic-level view of FimH in two-state conformational ensembles in solution, composed of one low-affinity tense (T) and multiple high-affinity relaxed (R) conformations. Positively selected residues allosterically modulate the equilibrium between these two conformational states, each of which engages mannose through distinct binding orientations. A FimH variant that only adopts the R state is severely attenuated early in a mouse model of uncomplicated UTI but is proficient at colonizing catheterized bladders in vivo or bladder transitional-like epithelial cells in vitro. Thus, the bladder habitat has barrier(s) to R state-mediated colonization possibly conferred by the terminally differentiated bladder epithelium and/or decoy receptors in urine. Together, our studies reveal the conformational landscape in solution, binding mechanisms, and adhesive strength of an allosteric two-domain adhesin that evolved "moderate" affinity to optimize persistence in the bladder during UTI.
authors.affiliation: Center for Women's Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Vasilios
authors.identifier: 0000-0001-9685-4139
authors.initials: V
authors.lastname: Kalas
authors.affiliation: Center for Women's Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Jerome S
authors.identifier: 0000-0002-7389-7440
authors.initials: JS
authors.lastname: Pinkner
authors.affiliation: Center for Women's Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Thomas J
authors.identifier: 0000-0003-0498-8231
authors.initials: TJ
authors.lastname: Hannan
authors.affiliation: Center for Women's Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Michael E
authors.identifier: 0000-0002-0072-6210
authors.initials: ME
authors.lastname: Hibbing
authors.affiliation: Center for Women's Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Karen W
authors.initials: KW
authors.lastname: Dodson
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: Alex S
authors.identifier: 0000-0002-4155-5729
authors.initials: AS
authors.lastname: Holehouse
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Niraj H
authors.initials: NH
authors.lastname: Tolia
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: Michael L
authors.identifier: 0000-0003-1159-4636
authors.initials: ML
authors.lastname: Gross
authors.affiliation: Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: Rohit V
authors.initials: RV
authors.lastname: Pappu
authors.affiliation: Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA.
authors.forename: James
authors.initials: J
authors.lastname: Janetka
authors.affiliation: Center for Women's Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.; Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Hultgren
mesh_terms: D018830:Adhesins, Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000818:Animals; D004926:Escherichia coli / Q000737:chemistry / Q000472:pathogenicity / Q000502:physiology; D004927:Escherichia coli Infections / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D005260:Female; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006790:Host-Parasite Interactions / Q000502:physiology*; D051379:Mice; D000072417:Protein Domains; D001743:Urinary Bladder / Q000378:metabolism / Q000382:microbiology / Q000502:physiology; D014552:Urinary Tract Infections / Q000235:genetics / Q000378:metabolism / Q000382:microbiology / Q000473:pathology
chemical_list: D018830:Adhesins, Escherichia coli; C058769:fimH protein, E coli; D036781:Fimbriae Proteins
keywords: Bladder epithelium; Chaperone usher pili; Escherichia coli; FimH; Molecular Tethering; Protein Allostery; Protein Conformation; Urinary tract infection; adhesin; positive selection