title: Reversible denaturation of the gene V protein of bacteriophage f1.
abstract: The guanidine hydrochloride (GuHCl)-induced denaturation of the gene V protein of bacteriophage f1 has been studied, using the chemical reactivity of a cysteine residue that is buried in the folded protein and the circular dichroism (CD) at 211 and 229 nm as measures of the fraction of polypeptide chains in the folded form. It is found that this dimeric protein unfolds in a single cooperative transition from a folded dimer to two unfolded monomers. A folded, monomeric form of the gene V protein was not detected at equilibrium. The kinetics of unfolding of the gene V protein in 3 M GuHCl and the refolding in 2 M GuHCl are also consistent with a transition between a folded dimer and two unfolded monomers. The GuHCl concentration dependence of the rates of folding and unfolding suggests that the transition state for folding is near the folded conformation.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637.
authors.forename: H
authors.initials: H
authors.lastname: Liang
authors.forename: T C
authors.initials: TC
authors.lastname: Terwilliger
mesh_terms: D003090:Coliphages / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000302:isolation & purification; D004926:Escherichia coli / Q000378:metabolism; D019791:Guanidine; D006146:Guanidines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011487:Protein Conformation; D011489:Protein Denaturation; D013816:Thermodynamics; D014764:Viral Proteins / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D004268:DNA-Binding Proteins; D006146:Guanidines; D014764:Viral Proteins; C057816:gene 5 protein, Enterobacteria phage M13; D019791:Guanidine