Phi values in protein-folding kinetics have energetic and structural components.
Phi values are experimental measures of how the kinetics of protein folding is changed by single-site mutations. Phi values measure energetic quantities, but they are often interpreted in terms of the structures of the transition-state ensemble. Here, we describe a simple analytical model of the folding kinetics in terms of the formation of protein substructures. The model shows that Phi values have both structural and energetic components. It also provides a natural and general interpretation of "nonclassical" Phi values (i.e., < 0 or > 1). The model reproduces the Phi values for 20 single-residue mutations in the alpha-helix of the protein CI2, including several nonclassical Phi values, in good agreement with experiments.
Merlo
Claudia
C
Max Planck Institute of Colloids and Interfaces, Theory Division, 14424 Potsdam, Germany.
Dill
Ken A
KA
Weikl
Thomas R
TR
D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D017510:Protein Folding; D011506:Proteins / Q000235:genetics*
D011506:Proteins