title: Intrinsic local destabilization of the C-terminus predisposes integrin α1 I domain to a conformational switch induced by collagen binding.
abstract: Integrin-collagen interactions play a critical role in a myriad of cellular functions that include immune response, and cell development and differentiation, yet their mechanism of binding is poorly understood. There is increasing evidence that conformational flexibility assumes a central role in the molecular mechanisms of protein-protein interactions and here we employ NMR hydrogen-deuterium exchange (HDX) experiments to explore the impact of slower timescale dynamic events. To gain insight into the mechanisms underlying collagen-induced conformational switches, we have undertaken a comparative study between the wild type integrin α1 I and a gain-of-function E317A mutant. NMR HDX results suggest a relationship between regions exhibiting a reduced local stability in the unbound I domain and those that undergo significant conformational changes upon binding. Specifically, the αC and α7 helices within the C-terminus are at the center of such major perturbations and present reduced local stabilities in the unbound state relative to other structural elements. Complementary isothermal titration calorimetry experiments have been performed to derive complete thermodynamic binding profiles for association of the collagen-like triple-helical peptide with wild type α1 I and E317A mutant. The differential energetics observed for E317A are consistent with the HDX experiments and support a model in which intrinsically destabilized regions predispose conformational rearrangement in the integrin I domain. This study highlights the importance of exploring different timescales to delineate allosteric and binding events.
authors.affiliation: Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.|Center for Integrative Proteomics Research, Rutgers University, Piscataway, New Jersey, 08854.
authors.forename: Ana Monica
authors.initials: AM
authors.lastname: Nunes
authors.affiliation: Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.|Center for Integrative Proteomics Research, Rutgers University, Piscataway, New Jersey, 08854.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.|Center for Integrative Proteomics Research, Rutgers University, Piscataway, New Jersey, 08854.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Jezioro
authors.affiliation: Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.
authors.forename: Conceição A S A
authors.initials: CA
authors.lastname: Minetti
authors.affiliation: Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.
authors.forename: David P
authors.initials: DP
authors.lastname: Remeta
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, United Kingdom.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Farndale
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, United Kingdom.
authors.forename: Samir W
authors.initials: SW
authors.lastname: Hamaia
authors.affiliation: Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854.|Center for Integrative Proteomics Research, Rutgers University, Piscataway, New Jersey, 08854.
authors.forename: Jean
authors.initials: J
authors.lastname: Baum
mesh_terms: D019943:Amino Acid Substitution; D003094:Collagen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D039423:Integrin alpha1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D019906:Nuclear Magnetic Resonance, Biomolecular; D000072417:Protein Domains; D055550:Protein Stability; D017433:Protein Structure, Secondary
chemical_list: D039423:Integrin alpha1; D003094:Collagen
keywords: NMR; alpha1 I domain; binding energetics; collagen; conformational switch; dynamics; hydrogen-deuterium exchange; integrin