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Volume 4 Nano Research & Applications
ISSN: 2471-9838
Notes:
JOINT EVENT
October 04-05, 2018 Moscow, Russia
&
2nd Edition of International Conference on
26th International Conference on Advanced Nanotechnology
Materials Technology and Manufacturing Innovations
Advanced Nanotechnology 2018
& Materials-Manufacturing 2018
October 04-05, 2018 Page 16
Haruo Sugi
Teikyo University School of Medicine, Japan
Haruo Sugi, Nano Res Appl 2018, Volume 4
DOI: 10.21767/2471-9838-C5-019
Myosin heads in muscle can sense presence or absence of actin filaments to decide the direction
of ATP-induced movement
Although almost 70 years have passed since themonumental discovery of Huxley andHanson; thatmuscle contraction
results from relative sliding between actin and myosin filaments, which in turn caused by cyclic attachment and
detachment between myosin heads extending from myosin filaments and the corresponding myosin binding sites in
actin filaments.The performance of myosin heads still remains to be amatter for debate and speculation.Themain reason
why the research work on the myosin head performance is retarded is asynchronous nature of myosin head movement;
experimental methods including muscle mechanics, chemical probes and time resolved X-ray diffraction can detect
only averaged myosin head movement with ambiguous results. To visualize and record myosin head movement coupled
with ATP hydrolysis, we developed the gas environmental chamber (EC), which enabled us to record ATP induced
power and recovery strokes in individual myosin heads in hydrated, living myosin filaments in the presence or absence
of actin filaments. Our results obtained from experiments using the EC have revealed the fundamental properties of
myosin heads in muscle, which can be summarized as follows: In the absence of actin filaments, myosin heads fluctuate
around the definite neutral position; on binding with applied ATP, myosin heads take the form of M-ADP-Pi (charged-
up state) to perform recovery stroke in the direction opposite to power stroke; after exhaustion of ATP, myosin heads
return to the neutral position; in the presence of actin filaments, myosin heads bind with applied ATP to take the form
of M-ADP-Pi (charged-up state) to perform power stroke while attached to actin filaments; after exhaustion of ATP,
myosin heads return to the neutral position. These results show that myosin heads can sense presence or absence of
actin filaments and decide the direction of ATP induced movement without being guided by actin filaments.
Biography
Haruo Sugi completed his postgraduate from the University of Tokyo and worked at the University of Tokyo Medical School, Columbia University and the
National Institutes of Health. He was Professor and Chairman in the Department of Physiology, Teikyo University Medical School from 1973 to 2004 when he
became Emeritus Professor. He was chairman of Muscle Commission in the International Union of Physiological Sciences from 1996 to 2006.