| Project/Area Number |
60480018
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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 |
動物発生・生理学
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| Research Institution | Chiba University |
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Principal Investigator |
MARUYAMA Koscak Department of Biology,Faculty of Science,Chiba University, 理学部, 教授 (60012267)
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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 |
¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥6,500,000 (Direct Cost: ¥6,500,000)
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| Keywords | connectin / elastic filament / striated muscle / サルコメア / 滑り説 / β-シート |
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| Research Abstract |
Connectin is a very long filamentous protein present in vertebrate striated myofibrils linking myosin filaments to neighboring Z lines in a sarcomere. This is the third filament in addition to myosin and actin filaments in muscle.
In the present study, circular dichroism spectra suggested that connectin consists of 70 % beta sheet structure and 30 % random coil. Artifially made connectin fibers showed X ray diffraction corrresponding to beta sheet structure as seen in silk fiboin. The fibers could be reversibly stretched up to 30 % of the initial length with tention generation. Temperature dependence of tention generation suggested that the elasticity was not a simple entropy elasticity. Further work is required for the detailed elastic structure of the connectin filaments.
It was observed that short actin filaments dispersed by sonication in the presence of beta-actinin formed a network by the addition of connectin. Binding of connectin to actin meshwork was studied by cosedimentation experiments. Tropomyosin did not interfere with the binding. However, Sl, myosin heads inhibited it. Thus when Sl was added to connectin-actin network, actin filaments decorated with Sl gradually released from the aggregate. Connectin evidently does not interfere with the actin myosin interaction, driving force for sliding.
From the present study, it is proposed that connectin filaments loosely bound to actin filaments in the I band region and acts as a guideline when sliding of the actin filaments occurs. Connectin filaments bind to the myosin filaments but it is regarded that myosin and actin interactions are not hindered by connectin at all.
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