EPR spectra and molecular dynamics agree that the nucleotide pocket of myosin V is closed and that it opens on binding actin.

ABSTRACT: We have used EPR spectroscopy and computational modeling of nucleotide-analog spin probes to investigate conformational changes at the nucleotide site of myosin V. We find that, in the absence of actin, the mobility of a spin-labeled diphosphate analog [spin-labeled ADP (SLADP)] bound at the active site is strongly hindered, suggesting a closed nucleotide pocket. The mobility of the analog increases when the MV·SLADP complex (MV=myosin V) binds to actin, implying an opening of the active site in the A·MV·SLADP complex (A=actin). The probe mobilities are similar to those seen with myosin II, despite the fact that myosin V has dramatically altered kinetics. Molecular dynamics (MD) simulation was used to understand the EPR spectra in terms of the X-ray database. The X-ray structure of MV·ADP·

SUBMITTER: Purcell TJ 

PROVIDER: S-EPMC3143297 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature