1
|
Kalas V, Pinkner JS, Hannan TJ, Hibbing ME, Dodson KW, Holehouse AS, Zhang H, Tolia NH, Gross ML, Pappu RV, Janetka J, Hultgren SJ. Evolutionary fine-tuning of conformational ensembles in FimH during host-pathogen interactions. Sci Adv 2017; 3:e1601944. [PMID: 28246638 PMCID: PMC5302871 DOI: 10.1126/sciadv.1601944] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/25/2017] [Indexed: 05/05/2023]
Abstract
Positive selection in the two-domain type 1 pilus adhesin FimH enhances Escherichia coli fitness 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.
Collapse
Affiliation(s)
- Vasilios Kalas
- 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
| | - Jerome S. Pinkner
- 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
| | - Thomas J. Hannan
- 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
| | - Michael E. Hibbing
- 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
| | - Karen W. Dodson
- 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
| | - Alex S. Holehouse
- 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
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Niraj H. Tolia
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Rohit V. Pappu
- 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
| | - James Janetka
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Scott J. Hultgren
- 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
- Corresponding author.
| |
Collapse
|
2
|
Pandyarajan V, Phillips NB, Cox GP, Yang Y, Whittaker J, Ismail-Beigi F, Weiss MA. Biophysical optimization of a therapeutic protein by nonstandard mutagenesis: studies of an iodo-insulin derivative. J Biol Chem 2014; 289:23367-81. [PMID: 24993826 DOI: 10.1074/jbc.m114.588277] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Insulin provides a model for the therapeutic application of protein engineering. A paradigm in molecular pharmacology was defined by design of rapid-acting insulin analogs for the prandial control of glycemia. Such analogs, a cornerstone of current diabetes regimens, exhibit accelerated subcutaneous absorption due to more rapid disassembly of oligomeric species relative to wild-type insulin. This strategy is limited by a molecular trade-off between accelerated disassembly and enhanced susceptibility to degradation. Here, we demonstrate that this trade-off may be circumvented by nonstandard mutagenesis. Our studies employed Lys(B28), Pro(B29)-insulin ("lispro") as a model prandial analog that is less thermodynamically stable and more susceptible to fibrillation than is wild-type insulin. We have discovered that substitution of an invariant tyrosine adjoining the engineered sites in lispro (Tyr(B26)) by 3-iodo-Tyr (i) augments its thermodynamic stability (ΔΔGu 0.5 ± 0.2 kcal/mol), (ii) delays onset of fibrillation (lag time on gentle agitation at 37 °C was prolonged by 4-fold), (iii) enhances affinity for the insulin receptor (1.5 ± 0.1-fold), and (iv) preserves biological activity in a rat model of diabetes mellitus. (1)H NMR studies suggest that the bulky iodo-substituent packs within a nonpolar interchain crevice. Remarkably, the 3-iodo-Tyr(B26) modification stabilizes an oligomeric form of insulin pertinent to pharmaceutical formulation (the R6 zinc hexamer) but preserves rapid disassembly of the oligomeric form pertinent to subcutaneous absorption (T6 hexamer). By exploiting this allosteric switch, 3-iodo-Tyr(B26)-lispro thus illustrates how a nonstandard amino acid substitution can mitigate the unfavorable biophysical properties of an engineered protein while retaining its advantages.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Michael A Weiss
- From the Departments of Biochemistry, Medicine, and Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106
| |
Collapse
|