Solvent-Exposed Salt Bridges Influence the Kinetics of α-Helix Folding and Unfolding.

ABSTRACT: Salt bridges are known to play an essential role in the thermodynamic stability of the folded conformation of many proteins, but their influence on the kinetics of folding remains largely unknown. Here, we investigate the effect of Glu-Arg salt bridges on the kinetics of α-helix folding using temperature-jump transient-infrared spectroscopy and steady-state UV circular dichroism. We find that geometrically optimized salt bridges (Glu^- and Arg⁺ are spaced four peptide units apart, and the Glu/Arg order is such that the side-chain rotameric preferences favor salt-bridge formation) significantly speed up folding and slow down unfolding, whereas salt bridges with unfavorable geometry slow down folding and slightly speed up unfolding. Our observations suggest a poss

SUBMITTER: Meuzelaar H 

PROVIDER: S-EPMC3948500 | biostudies-literature | 2014 Mar

REPOSITORIES: biostudies-literature