Step-size of net filament sliding of muscle contraction.
The step-size defined as the movement between actin and myosin filaments per ATP split is an important issue in the research of muscle contraction. According to the conventional swinging-cross-bridge theory by Huxley, the step-size in this sense should be within 40 nm, a maximum possible stroke size of a myosin head, 20 nm, swing through an arc of 180 degrees . Since 1996, the estimated value over 40 nm has not been reported. Recently, however, there have been several discussions based on the one of the smallest values of step-size, 1.7 nm. We carefully re-evaluated the estimation process for the step-size, concluding that the values are still limited within 10-20 nm of conventional swinging-cross-bridge theory: 12.6 nm at no load for frog muscle.
Division of Medical Information Science, Department of Social Medicine, School of Medicine, Akita University, 1-1-1 Hondo, Akita City 010-8543, Japan.
Tsann-Chung
TC
Wu
Akira
A
Nakamura
D000199:Actins / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D006358:Hot Temperature; D006868:Hydrolysis; D015233:Models, Statistical; D008962:Models, Theoretical; D009068:Movement; D009119:Muscle Contraction; D009218:Myosins / Q000737:chemistry*; D011898:Ranidae; D012518:Sarcomeres / Q000378:metabolism; D013696:Temperature; D013816:Thermodynamics
D000199:Actins; D000255:Adenosine Triphosphate; D009218:Myosins