Structural dynamics of the myosin relay helix by time-resolved EPR and FRET.

ABSTRACT: We have used two complementary time-resolved spectroscopic techniques, dipolar electron-electron resonance and fluorescence resonance energy transfer to determine conformational changes in a single structural element of the myosin motor domain, the relay helix, before and after the recovery stroke. Two double-Cys mutants were labeled with optical probes or spin labels, and interprobe distances were determined. Both methods resolved two distinct structural states of myosin, corresponding to straight and bent conformations of the relay helix. The bent state was occupied only upon nucleotide addition, indicating that relay helix, like the entire myosin head, bends in the recovery stroke. However, saturation of myosin with nucleotide, producing a single biochemical state, did not produce a sin

SUBMITTER: Agafonov RV 

PROVIDER: S-EPMC2799882 | biostudies-literature | 2009 Dec

REPOSITORIES: biostudies-literature