Direct observation of a force-induced switch in the anisotropic mechanical unfolding pathway of a protein.

ABSTRACT: Many biological processes generate force, and proteins have evolved to resist and respond to tension along different force axes. Single-molecule force spectroscopy allows for molecular insight into the behavior of proteins under force and the mechanism of protein folding in general. Here, we have used src SH3 to investigate the effect of different pulling axes under the low-force regime afforded by an optical trap. We find that this small cooperatively folded protein shows an anisotropic response to force; the protein is more mechanically resistant to force applied along a longitudinal axis compared to force applied perpendicular to the terminal β strand. In the longitudinal axis, we observe an unusual biphasic behavior revealing a force-induced switch in the unfolding mechanism suggesting

SUBMITTER: Jagannathan B 

PROVIDER: S-EPMC3497811 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature