Science 15 February 2008:
Vol. 319. no. 5865, pp. 955 - 958
DOI: 10.1126/science.1151343



Axle-Less F1-ATPase Rotates in the Correct Direction

Shou Furuike,1*Mohammad Delawar Hossain,1,2* Yasushi Maki,3 Kengo Adachi,1 Toshiharu Suzuki,4,5 Ayako Kohori,1 Hiroyasu Itoh,6,7 Masasuke Yoshida,4,5 Kazuhiko Kinosita, Jr.1

F1–adenosine triphosphatase (ATPase) is an ATP-driven rotary molecular motor in which the central γ subunit rotates inside a cylinder made of three α and three β subunits alternately arranged. The rotor shaft, an antiparallel α-helical coiled coil of the amino and carboxyl termini of the γ subunit, deeply penetrates the central cavity of the stator cylinder. We truncated the shaft step by step until the remaining rotor head would be outside the cavity and simply sat on the concave entrance of the stator orifice. All truncation mutants rotated in the correct direction, implying torque generation, although the average rotary speeds were low and short mutants exhibited moments of irregular motion. Neither a fixed pivot nor a rigid axle was needed for rotation of F1-ATPase.

1 Department of Physics, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 169-8555, Japan.
2 Department of Physics, School of Physical Sciences, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh.
3 Department of Physics, Osaka Medical College, Osaka 569-8686, Japan.
4 Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259, Yokohama 226-8503, Japan.
5 ATP-Synthesis Regulation Project, International Cooperative Research Project (ICORP), Japan Science and Technology Agency (JST), Aomi 2-41, Tokyo 135-0064, Japan.
6 Tsukuba Research Laboratory, Hamamatsu Photonics KK, Tokodai, Tsukuba 300-2635, Japan.
7 Core Research for Evolutional Science and Technology (CREST) "Formation of Soft Nano-Machines" Team 13*, Tokodai, Tsukuba 300-2635, Japan.

  * These authors contributed equally to this work.

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