1986 Fiscal Year Final Research Report Summary
The Effects of Calcium Ions on the Structure of the Thin Filament
| Project/Area Number |
60580205
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
YAGI Naoto Department of Pharmacology, Tohoku University School of Medicine, 医学部, 助手 (80133940)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUBARA Ichiro Department of Pharmacology, Tohoku University School of Medicine, 医学部, 助教授 (90010040)
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| Project Period (FY) |
1985 – 1986
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| Keywords | muscle / X-ray diffraction / calcium / 細いフィラメント |
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| Research Abstract |
The intensity changes of the actin layer-lines during activation of sartorius and overstretched semitendinosus muscles were measured by using a two-dimensional position sensitive X-ray detector. In both muscles, the intensity of the 5.9nm layer-line increased without a detectable shift in the peak position. The intensity of the second layer-line increased in both muscles by a similar amount. In semitendinosus muscle, the intensities of the equator, the second layer-line and the 5.9nm layer-line increased while that of the first layer-line decreased during activation. The large decrease in the intensity of the first layer-line is not explained by a simplified model of the structural change in the thin filament involving the tropomyosin shift and might explain the apparent absence of the intensity increase of this layer-line during contraction of sartorius muscle. The experments made by using synchrotron radiation showed that the intensity change of the second layer-line is very fast. This confirms that this intensity change is associated with the structural changes in the thin filament which take place when calcium ions bind to troponin.
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