| Project/Area Number |
09680658
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biophysics
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| Research Institution | Science University of Tokyo |
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Principal Investigator |
YAMADA Takenori Sci. Univ. of Tokyo, Dept. of physics, Professor, 理学部, 教授 (50027330)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Muscle contraction / Actin / Myosin / Sarcomere / Molecular field / Atomic force microscope (CONTINUE TO NEXT PAGE) / Laser tweezer / 生物分子モーター / 原始間力顕微鏡 / ミオフィブリル / 筋収縮 / 筋節 |
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| Research Abstract |
Recently a ratchet model has been proposed for the molecular mechanism of actomyosin sliding where unidirectional thermal diffusion of myosin head takes place along asymmetric molecular field of actin filament. The purpose of the present research is to obtain experimental evidence for asymmetric molecular field along myofilaments. Firstly the contractility of single myofibrils was studied under isometric conditions (Yuri et al., 1998), and then during shortenings (submitted). Then the surface molecular field of myofibril was studied by use of an atomic force microscope to obtain transverse elasticity distribution along sarcomere (Yoshikawa et al., 1999). By analysing the longitudinal and transverse elesticities of myofibril, we found the elasticity of single attached cross-bridge has the structural asymmetry (in preparation). To study the molecular field along actin and myosin filaments in detail, trials were made to prepare cantilever with a ZnO wisker and obtain AFM images of actin and myosin filaments by use of this cantilever. Separately, by use of a laser tweezer system, single actin filament was suspended between two immobilized beads, and a bead coated with myosin was made to slide along the actin filament. By analysing the movements of myosin-coated beads along actin filament, the molecular field present between actin and myosin interface was examined. These studies supported the presence of asymmetric molecular field along myofi1aments, which is in accord with the ratchet theory. Further detailed studies of internal structures of the molecular field of myofilaments are required to clearly the molecular mechanism of muscle contraction.
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