Broad disorder and the allosteric mechanism of myosin II regulation by phosphorylation.

ABSTRACT: Double electron electron resonance EPR methods was used to measure the effects of the allosteric modulators, phosphorylation, and ATP, on the distances and distance distributions between the two regulatory light chain of myosin (RLC). Three different states of smooth muscle myosin (SMM) were studied: monomers, the short-tailed subfragment heavy meromyosin, and SMM filaments. We reconstituted myosin with nine single cysteine spin-labeled RLC. For all mutants we found a broad distribution of distances that could not be explained by spin-label rotamer diversity. For SMM and heavy meromyosin, several sites showed two heterogeneous populations in the unphosphorylated samples, whereas only one was observed after phosphorylation. The data were consistent with the presence of two coexisting hetero

SUBMITTER: Vileno B 

PROVIDER: S-EPMC3100986 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature