Amplitude of the actomyosin power stroke depends strongly on the isoform of the myosin essential light chain.

ABSTRACT: We have used time-resolved fluorescence resonance energy transfer (TR-FRET) to determine the role of myosin essential light chains (ELCs) in structural transitions within the actomyosin complex. Skeletal muscle myosins have two ELC isoforms, A1 and A2, which differ by an additional 40-45 residues at the N terminus of A1, and subfragment 1 (S1) containing A1 (S1A1) has higher catalytic efficiency and higher affinity for actin than S1A2. ELC's location at the junction between the catalytic and light-chain domains gives it the potential to play a central role in the force-generating power stroke. Therefore, we measured site-directed TR-FRET between a donor on actin and an acceptor near the C terminus of ELC, detecting directly the rotation of the light-chain domain (lever arm) relative to act

SUBMITTER: Guhathakurta P 

PROVIDER: S-EPMC4403186 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature