1996 Fiscal Year Final Research Report Summary
Molecular Energetics of Protein Motors
| Project/Area Number |
06304052
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 総合 |
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| Research Field |
Biophysics
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| Research Institution | KYUSHU INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
KODAMA Takao KYUSHU INSTITUTE OF TECHNOLOGY,FACULTY OF COMPUTER SCIENCE AND ENGINEERING,PROFESSOR, 情報工学部, 教授 (30034200)
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| Co-Investigator(Kenkyū-buntansha) |
TAWADA Katsuhisa KYUSHU UNIVERSITY,FACULTY OF SCIENCE,ASSOCIATE PROFESSOR, 理学部, 助教授 (20029507)
KATAYAMA Eisaku UNIVERSITY OF TOKYO,BIOMEDICAL INSTITUTE,ASSOCIATE PROFESSOR, 医科学研究所, 助教授 (50111505)
WAKABAYASHI Katsuzo OSAKA UNIVERSITY,FACULTY OF ENGINEERING SCIENCE,ASSOCIATE PROFESSOR, 基礎工学部, 助教授 (00029521)
WAKABAYASHI Takeyuki UNIVERSITY OF TOKYO,GRADUATE SCHOOL OF SCIENCE,PROFESSOR, 大学院・理学系研究科, 教授 (90011717)
YANAGIDA Toshio OSAKA UNIVERSITY,FACULTY OF ENGINEERING SCIENCE,PROFESSOR, 基礎工学部, 教授 (30089883)
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| Project Period (FY) |
1994 – 1996
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| Keywords | chemomechanical coupling / hydrophobic / hydrophilc transition / single molecule physiology / thermal fluctuation / ATP ase / vectorial motion / intramolecular hydrogen-bond / motor molecule |
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| Research Abstract |
Energetic aspects of protein motors were investigated by various methods including microwave-dielectric spectroscopy and calorimetry of myosin motors hydrolyzind ATP,direct observation of simgle kinesin molecules moving along microtubules, imaging of individual ATP turnovers by single myosin molecules, small-angle X-ray diffeaction of myosin molecules with diffrrent bound nucleotides, X-ray diffraction of muscle, X-ray crystallography of myosin complexed with different nucleotides, diffusion-enhanced fluorescence resonance energy transfer of actin molecules, simulation of solvation free-energy of protein motors, fluctuation analysis of kinesin sliding along microtubule, stereo-photogramtry of quick-freeze deep-etch replica images of motor proteins, and site-directed mutagenesis of motor proteins. These studies indicate that :
1.the myosin surface hydrophobicity change plays a crucial role in the enthalpy-entropy compensation effectc observed in the steps of myosin ATP hydrolysis ;
2.protein motors can modulate the mode of coupling between chemical change (ATP hydrolysis) and mechanical output depending on load imposed on them. Thus, the energy of ATP hydrolys is somehow stored in the motor protein, which is used fractionally at each power stroke cycle. This would mean that the protein motor operate with energy conversion efficiency as high as more than 50% using the energy input comparable to or marginally above the thermal energy ;
3.Of two negative potential sites of actin molecule surface, one around the myosin binding site while the other site around the phalloidin binding site is not significantly affected ;
4.an effective diffusion coefficient from displacement fluctuations of a sliding filament obtained from its single noisy trajectory is a useful parameters for constructing the models for mechanochemical coupling.
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