Effect of urea on peptide conformation in water: molecular dynamics and experimental characterization.

ABSTRACT: Molecular dynamics simulations of a ribonuclease A C-peptide analog and a sequence variant were performed in water at 277 and 300 K and in 8 M urea to clarify the molecular denaturation mechanism induced by urea and the early events in protein unfolding. Spectroscopic characterization of the peptides showed that the C-peptide analog had a high alpha-helical content, which was not the case for the variant. In the simulations, interdependent side-chain interactions were responsible for the high stability of the alpha-helical C-peptide analog in the different solvents. The other peptide displayed alpha-helical unwinding that propagated cooperatively toward the N-terminal. The conformations sampled by the peptides depended on their sequence and on the solvent. The ability of water molecules to

SUBMITTER: Caballero-Herrera A 

PROVIDER: S-EPMC1366634 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature