| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
* Department of Physics, Faculty of Science and Engineering, Waseda University, Tokyo 169-8555, Japan; Department of Physics, School of Physical Sciences, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh; Department of Physics, Faculty of Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh; Department of Biology, Faculty of Science, Niigata University, Niigata 950-2181, Japan; ¶ Tsukuba Research Laboratory, Hamamatsu Photonics KK, and || CREST "Creation and Application of Soft Nano-Machine, the Hyperfunctional Molecular Machine" Team 13, Tokodai, Tsukuba 300-2635, Japan; ** Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan; and ERATO "ATP System", Japan Science and Technology Agency, Yokohama 226-0026, Japan
Correspondence: Address reprint requests to Kazuhiko Kinosita Jr., Dept. of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan. Tel.: 81-3-5952-5871; Fax: 81-3-5952-5877; E-mail: kazuhiko{at}waseda.jp.
F1-ATPase is an ATP-driven rotary molecular motor in which the central 
-subunit rotates inside a stator cylinder made of 
3ß3 subunits. To elucidate the role of rotor-stator interactions in torque generation, we truncated the -subunit at its carboxyl terminus, which forms an helix that penetrates deeply into the stator cylinder. We used an 3ß3 subcomplex of F1-ATPase derived from thermophilic Bacillus PS3 and expressed it in Escherichia coli. We could obtain purified subcomplexes in which 14, 17, or 21 amino-acid residues were deleted. The rotary characteristics of the truncated mutants, monitored by attaching a duplex of 0.49-µm beads to the -subunit, did not differ greatly from those of the wild-type over the ATP concentrations of 20 nM–2 mM, the most conspicuous effect being 
50% reduction in torque and 70% reduction in the rate of ATP binding upon deletion of 21 residues. The ATP hydrolysis activity estimated in bulk samples was more seriously affected. The 21-deletion mutant, in particular, was >10-fold less active, but this is likely due to instability of this subcomplex. For torque generation, though not for rapid catalysis, most of the rotor-stator contacts on the deeper half of the penetrating portion of the -subunit are dispensable.
This article has been cited by other articles:
 |
|
 |
|
  H. Sielaff, H. Rennekamp, A. Wachter, H. Xie, F. Hilbers, K. Feldbauer, S. D. Dunn, S. Engelbrecht, and W. Junge Domain compliance and elastic power transmission in rotary FOF1-ATPase PNAS, November 18, 2008; 105(46): 17760 - 17765. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. D. Hossain, S. Furuike, Y. Maki, K. Adachi, T. Suzuki, A. Kohori, H. Itoh, M. Yoshida, and K. Kinosita Jr. Neither Helix in the Coiled Coil Region of the Axle of F1-ATPase Plays a Significant Role in Torque Production Biophys. J., November 15, 2008; 95(10): 4837 - 4844. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Furuike, M. D. Hossain, Y. Maki, K. Adachi, T. Suzuki, A. Kohori, H. Itoh, M. Yoshida, and K. Kinosita Jr. Axle-Less F1-ATPase Rotates in the Correct Direction Science, February 15, 2008; 319(5865): 955 - 958. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Pu and M. Karplus How subunit coupling produces the {gamma}-subunit rotary motion in F1-ATPase PNAS, January 29, 2008; 105(4): 1192 - 1197. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
