Electron microscopic recording of myosin head power stroke in hydrated myosin filaments
Citations Over TimeTop 13% of 2015 papers
Abstract
Muscle contraction results from cyclic attachment and detachment between myosin heads and actin filaments, coupled with ATP hydrolysis. Despite extensive studies, however, the amplitude of myosin head power stroke still remains to be a mystery. Using the gas environmental chamber, we have succeeded in recording the power stroke of position-marked myosin heads in hydrated mixture of actin and myosin filaments in a nearly isometric condition, in which myosin heads do not produce gross myofilament sliding, but only stretch adjacent elastic structures. On application of ATP, individual myosin heads move by ~3.3 nm at the distal region, and by ~2.5 nm at the proximal region of myosin head catalytic domain. After exhaustion of applied ATP, individual myosin heads return towards their initial position. At low ionic strength, the amplitude of myosin head power stroke increases to >4 nm at both distal and proximal regions of myosin heads catalytic domain, being consistent with the report that the force generated by individual myosin heads in muscle fibers is enhanced at low ionic strength. The advantages of the present study over other in vitro motility assay systems, using myosin heads detached from myosin filaments, are discussed.
Related Papers
- → Myosin light chain kinase steady‐state kinetics: comparison of smooth muscle myosin II and nonmuscle myosin IIB as substrates(2016)13 cited
- → The role of the skeletal muscle myosin light chains N‐terminal fragments(1995)24 cited
- → Phosphorylation and activation of smooth muscle myosin by Acanthamoeba myosin I heavy chain kinase.(1984)23 cited
- → Ca2+ Regulation Not Associated with Phosphorylation of Myosin Light Chain in Aortic Intima Smooth Muscle, II. Effects of Regulatory Proteins on the Actin-Myosin Interaction(1983)4 cited
- → Interaction Between Two Myosin Heads in Acto-Smooth Muscle Heavy Meromyosin Rigor Complex(1993)