Energetic and structural consequences of desolvation/solvation barriers to protein folding/unfolding assessed from experimental unfolding rates.
Theoretical work has suggested the existence of solvation/desolvation barriers in protein folding/unfolding processes. We propose that the energetic and structural consequences of such barriers for the folding transition state can be assessed from experimental unfolding rates using well-established structure-energetics relationships. For a set of proteins of size within the 60-130 number-of-residues range, we find energetic effects associated to solvation/desolvation on the order of 10(2) kJ/mol. This supports that the folding transition states may be characterized by large networks of water-unsatisfied, broken internal contacts. In terms of buried surface, we estimate the typical network size to be on the order of several thousands of A2, or approximately 50% of the total change in accessible surface area upon unfolding. The analyses reported here thus suggest a clear structural picture for the different energetic balance of native and folding transition states.
Rodriguez-Larrea
David
D
Facultad de Ciencias, Departamento de Quimica Fisica, 18071-Granada, Spain.
Ibarra-Molero
Beatriz
B
Sanchez-Ruiz
Jose M
JM
D003198:Computer Simulation; D004735:Energy Transfer; D008956:Models, Chemical; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry* / Q000648:ultrastructure*; D012997:Solvents / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D011506:Proteins; D012997:Solvents; D014867:Water