Minimum energy compact structures in force-quench polyubiquitin folding are domain swapped.

ABSTRACT: Single molecule experiments that initiate folding using mechanical force are uniquely suited to reveal the nature of populated states in the folding process. Using a strategy proposed on theoretical grounds, which calls for repeated cycling of force from high to low values using force pulses, it was demonstrated in atomic force spectroscopy (AFM) experiments that an ensemble of minimum energy compact structures (MECS) are sampled during the folding of polyubiquitin. The structures in the ensemble are mechanically resistant to a lesser extent than the native state. Remarkably, forced unfolding of the populated intermediates reveals a broad distribution of extensions including steps up to 30 nm and beyond. We show using molecular simulations that favorable interdomain interactions leading to

SUBMITTER: Xia F 

PROVIDER: S-EPMC3084125 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature