Probing osmolyte participation in the unfolding transition state of a protein.

ABSTRACT: Understanding the molecular mechanisms of osmolyte protection in protein stability has proved to be challenging. In particular, little is known about the role of osmolytes in the structure of the unfolding transition state of a protein, the main determinant of its dynamics. We have developed an experimental protocol to directly probe the transition state of a protein in a range of osmolyte environments. We use an atomic force microscope in force-clamp mode to apply mechanical forces to the protein I27 and obtain force-dependent rate constants of protein unfolding. We measure the distance to the unfolding transition state, Δx(u), along a 1D reaction coordinate imposed by mechanical force. We find that for the small osmolytes, ethylene glycol, propylene glycol, and glycerol, Δx(u) scales wit

SUBMITTER: Dougan L 

PROVIDER: S-EPMC3116423 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature