title: Protein stability and electrostatic interactions between solvent exposed charged side chains.
abstract: To investigate the contribution to protein stability of electrostatic interactions between charged surface residues, we have studied the effect of substituting three negatively charged solvent exposed residues with their side-chain amide analogs in bovine calbindin D9k--a small (Mr 8,500) globular protein of the calmodulin superfamily. The free energy of urea-induced unfolding for the wild-type and seven mutant proteins has been measured. The mutant proteins have increased stability towards unfolding relative to the wild-type. The experimental results correlate reasonably well with theoretically calculated relative free energies of unfolding and show that electrostatic interactions between charges on the surface of a protein can have significant effects on protein stability.
authors.affiliation: Physical Chemistry 2, Lund University, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Akke
authors.forename: S
authors.initials: S
authors.lastname: Forsén
mesh_terms: D001059:Apoproteins / Q000235:genetics / Q000378:metabolism*; D064026:Calbindins; D004926:Escherichia coli / Q000235:genetics; D008958:Models, Molecular; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D064030:S100 Calcium Binding Protein G / Q000235:genetics / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D001059:Apoproteins; D064026:Calbindins; D064030:S100 Calcium Binding Protein G