Axis-dependent anisotropy in protein unfolding from integrated nonequilibrium single-molecule experiments, analysis, and simulation.

ABSTRACT: We present a comprehensive study that integrates experimental and theoretical nonequilibrium techniques to map energy landscapes along well defined pull-axis specific coordinates to elucidate mechanisms of protein unfolding. Single-molecule force-extension experiments along two different axes of photoactive yellow protein combined with nonequilibrium statistical mechanical analysis and atomistic simulation reveal energetic and mechanistic anisotropy. Steered molecular dynamics simulations and free-energy curves constructed from the experimental results reveal that unfolding along one axis exhibits a transition-state-like feature where six hydrogen bonds break simultaneously with weak interactions observed during further unfolding. The other axis exhibits a constant (unpeaked) force profile

SUBMITTER: Nome RA 

PROVIDER: S-EPMC2410074 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature