2010 Fiscal Year Final Research Report
Structure, rotation and regulation of ATP synthase(FoF1)
| Project/Area Number |
18107004
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional biochemistry
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| Research Institution | Kyoto Sangyo University (2010)
Tokyo Institute of Technology (2006-2009) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
HISABORI Toru 東京工業大学, 資源化学研究所, 教授 (40181094)
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| Co-Investigator(Renkei-kenkyūsha) |
MURAKAMI Satoshi 東京工業大学, 生命理工学部, 教授 (30300966)
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| Project Period (FY) |
2006 – 2010
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| Keywords | ATP合成 / ATP合成酵素 / F_oF_1 / モータータンパク質 / 生体エネルギー |
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| Research Abstract |
We made F_1-ATPases containing one or two mutant. β subunits that have the altered catalytic kinetics. The analysis of their asymmetric stepwise rotations reveal that, when watching one. β subunit in F_1-ATPase, it binds ATP at 0°, cleaves ATP after～ 200°rotation, and undergoes the final catalytic event, presumably the product release, after～ 320°rotation. Three. β subunits carry out this cycle at 120°difference like "trolling a tune" and their cyclic inter-domain bending motions would induce the rotation of γ subunit.
Rotation of the central shaft γ subunit in a molecular motor F_1-ATPase is assumed to correlate with and probably be driven by domain motions of the three catalytic. β subunits. Here we observe directly these. β motions through an attached fluorophore, concomitantly with 80 degrees and 40 degrees substep rotations of γ in the same single molecules. We show the sequence of conformations that each β subunit undergoes in three-step bending, an approximately 40 degrees counterclockwise turn followed by two approximately 20 degrees clockwise turns, occurring in synchronization with two substep rotations of γ. The results indicate that most previous crystal structures mimic the conformational set of three β subunits in the catalytic dwells. Moreover, a previously undescribed set of β conformations, open, closed and partially closed, is revealed in the ATP-waiting dwells. The present study thus bridges the gap between the chemical and mechanical steps in F_1-ATPase.
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