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1989 Fiscal Year Final Research Report Summary

ANALYSIS OF THE CONFORMATIONAL CHANGE ASSOCIATED WITH THE SLIDING MOVEMENT OF MYOSIN ALONG ACTIN FILAMENT

Research Project

Project/Area Number 63480508
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 分子遺伝学・分子生理学
Research InstitutionFACULTY OF MEDICINE, THE UNIVERSITY OF TOKYO

Principal Investigator

KATAYAMA Eisaku  UNIVERSITY OF TOKYO, DEPT. OF PHARMACOLOGY RESEARCH ASSOCIATE, 医学部(医), 文部教官助手 (50111505)

Project Period (FY) 1988 – 1989
Keywordsmuscle contraction / myosin / actin / sliding movement / conformation / smooth muscle / caldesmen / Ca^<2+>-regulation
Research Abstract

I attempted to observe the structure of muscle cross-bridges or myosin heads while sliding along thin filaments, with high special and temporal resolution obtained by quick-freezing electron microscopy, since any structural change accompanied with the sliding could be crucial to elucidate the molecular mechanism of "sliding movement". The study was started with the simplest system; a mixture of purified myosin subfragment-1 (S1) and F-actin as test specimen, to avoid the difficulty which arises from using whole muscle fiber; i.e.) the structural change in each head cannot be homogenous because of the restriction not only by two connected heads in a single molecule, but also by forming thick filaments. Using improved mica-flake technique coupled with quick-freeze deep-etch method, I presented the evidences, for the first time, indicating that S1 molecules appear elongated and attached to actin in a tilted manner under rigor condition or in the presence of ADP, whereas they are short and rounded if ADP.Vi or ATP is incorporated. Subsequent observation of heavy meromyosin molecules; each having two heads but does not form filament; in the presence of various nucleotides made it clear that the observed rounding of S1 would have come from the flection in myosin head. Though the presence of such large conformational change in myosin head has never been observed by electron microscopy, accumulating evidences from recent biochemical studies are quite compatible with this observation. Myosin heads seen in actomysin specimen during superprecipitation; the putative in vitro model system corresponding to muscle contraction; showed a similar morphological feature, suggesting the possibility that such conformational change actually occurring in actively contracting muscle.
Several new findings were also obtained concerning the functional domain organization and the conformation in solution, of caldesmon; the putative regulatory protein involved in smooth muscle contraction.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] E.Katayama: "The Effect of Vanous Nucleotides on the Stracture of Actin-Attached Myosin Subfrdgment-1 Studied by Quick-Freeze Deep-Etch Electron Microscopy" J.Biochemistry. 106. 751-770 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] E.Katayama,K.Y.Horiuchi&S.Chacko: "Characteristics of the Myosin and tropomyosin Binding Regions of the Smo9oth Muscle Caldesmon" Biochemical and Biophysical Research Communications. 160. 1316-1322 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] E.Katayama: "Assignment of the Positions of Chymotryptic Fragments and Cysteiryl Groups in the Primary Structure of Caldesmon in Relation to a Conformational Change" J.Biochemistry. 106. 988-993 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] E.Katayama,K.Y.Horichi&S.K.Chacko: "Binding of Proteolytic Fragments of Caldesmon to Myosin and Tropomyosin" Biophysical Journal. 55. 232a (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 片山栄作: "クロスブリッジの動き(光学顕微鏡および電子顕微鏡による研究を中心にして)" 実験医学. 17. 1882-1889 (1989)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 片山栄作: "マイカ細片法" 実験医学(印刷中). 18. (1990)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] E. Katayama: "The effect of various nucleotides on the structure of actin-attached myosin subfragment-1 studied by quick-freeze deep-etch electron microscopy" J. Biochem. 106,(5) 751-770 (1989).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E. Katayama, K.Y. Horiuchi & S. Chacko: "Characteristics of the myosin and tropomyosin binding regions of the smooth muscle caldesmon" Biochem. Biophys. Res. Commun. 160,(3) 1316-1322 (1989).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E. Katayama: "Assignment of the positions of chymotryptic fragments and cysteinyl groups in the primary structure of caldesmon in relation to a conformational change" J. Biochem. 106,(6) 988-993 (1989).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E. Katayama, K.Y. Horiuchi & S. Chacko: "Binding of proteolytic fragments of caldesmon to myosin and tropomyosin" Biophys. J. 55,(2, pt.2) 232a (1989).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E. Katayama, K.Y. Horiuchi & S. Chacko: "Functional domain organization in caldesmon molecule" Jpn. J. of Pharmacol. 49, (Suppl.) 279p (1989).

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] E. Katayama: "Conformational change of heavy meromyosin upon addition of nucleotides as studied by quick-freeze deep-etch electron microscopy" Abstracts for 10th Internat'l Congress of Biophysics.

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1993-03-26  

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