| Project/Area Number |
60480509
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
分子遺伝学・分子生理学
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| Research Institution | Faculty of Science, Nagoya University |
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Principal Investigator |
HIGASHI-FUJIME Sugie Institute of Molecular Biology, Faculty of Science, Nagoya University., 理学部, 助手 (60022662)
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| Co-Investigator(Kenkyū-buntansha) |
OWARIBE Katsushi Institute of Molecular Biology, Faculty of Science, Nagoya University., 理学部, 助手 (90109257)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1985: ¥5,300,000 (Direct Cost: ¥5,300,000)
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| Keywords | In vitro movement / Actomyosin / Dark field microscopy / Sliding theory / Heavy-meromyosin / 筋収縮 |
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| Research Abstract |
Various types of cell movements as well as muscle contraction, are based on actin-myosin interaction. Direct observation of in vitro movement of actomyosin at the molecular level revealed that single myosin filaments moved along an F-actin filament at 6 um/s which was independent of lengths of myosin filaments. The results infered that one myosin molecule could move along F-actin filament at 6 um/s.
Copolymers consisting of myosin and rod or LMM, in which myosin content in a filament was reduced, slid at the same velocity as that of myosin filaments at the molar fraction of myosin = 0.1. Travel distance and the number of moving filaments, however, decreased markedly. At the molar fraction 0.1, thermal motion interferes with observation of active movements and make it difficult to investigate capavility of sliding of one myosin molecule.
Another new finding was that actin filaments could be moved by HMM attached on a glass surface at 2 um/s under [KCL] = 35 mM, and by myosin at 3 um/s under [KCL] = 55 mM. This fact indicates that myosin head, but not the hinge region is responsible for force generation for sliding between actin and myosin filaments. Sliding velocities by myosin or HMM were independent of actin filament lengths (0.5-7 um), which suggested again that myosin molecules interacting with an F-actin might not cooperate with each other, and only one myosin molecule is able to move an F-actin filament continuously at 3 um/s.
Further investigation along this line will give us information for deep understanding about the molecular mechanism of muscle contraction and cell motility.
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