Molecular origin of constant m-values, denatured state collapse, and residue-dependent transition midpoints in globular proteins.

ABSTRACT: Experiments show that for many two-state folders the free energy of the native state, DeltaG(ND)([C]), changes linearly as the denaturant concentration, [C], is varied. The slope {m = [dDeltaG(ND)([C])]/(d[C])}, is nearly constant. According to the transfer model, the m-value is associated with the difference in the surface area between the native (N) and denatured (D) state, which should be a function of DeltaR(g)(2), the difference in the square of the radius of gyration between the D and N states. Single-molecule experiments show that the R(g) of the structurally heterogeneous denatured state undergoes an equilibrium collapse transition as [C] decreases, which implies m also should be [C]-dependent. We resolve the conundrum between constant m-values and [C]-dependent changes in R(g) usi

SUBMITTER: O'Brien EP 

PROVIDER: S-EPMC5551902 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature