Mechanism of titin unfolding by force: insight from quasi-equilibrium molecular dynamics calculations.

ABSTRACT: We have studied the unfolding by force of one of the immunoglobulin domains of the muscle protein titin using molecular dynamics simulations at 300 K. Previous studies, done at constant pulling rates, showed that under the effect of the force two strands connected to each other by six backbone H-bonds are pulled apart. No details about the mechanism of H-bond breaking were provided. Our simulation protocol "pull and wait" was designed to correspond to very slow pulling, more similar to the rates used in experiments than are the protocols used in previous computational studies. Under these conditions interstrand backbone H-bonds are not "ripped apart" by the application of the force. Instead, small elongations produced by the force weaken specific backbone H-bonds with respect to water-back

SUBMITTER: Pabon G 

PROVIDER: S-EPMC1483073 | biostudies-literature | 2006 Jul

REPOSITORIES: biostudies-literature