Myosin isoform determines the conformational dynamics and cooperativity of actin filaments in the strongly bound actomyosin complex.

ABSTRACT: We used transient phosphorescence anisotropy to detect the microsecond rotational dynamics of erythrosin-iodoacetamide-labeled actin strongly bound to single-headed fragments of muscle myosin subfragment 1 (S1) and non-muscle myosin V (MV). The conformational dynamics of actin filaments in solution are markedly influenced by the isoform of bound myosin. Both myosins increase the final anisotropy of actin at substoichiometric binding densities, indicating long-range, non-nearest neighbor cooperative restriction of filament rotational dynamics amplitude, but the cooperative unit is larger with MV than with muscle S1. Both myosin isoforms also cooperatively affect the actin filament rotational correlation time, but with opposite effects: muscle S1 decreases rates of intrafilament torsional mo

SUBMITTER: Prochniewicz E 

PROVIDER: S-EPMC2834967 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature