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 “Molecular mechanism and robustness of rotary catalysis of F1-ATPase”

 

        Date:

    Download-files:

      Time:

 Thursday, 06. Sept. 2018

    Video-Recording for any system with MP4-support

   - Video.mp4  (ca.425 Mb)

 15:15 – 16:25

 

                                   

                                                             Hiroyuki Noji

                                                           (University of Tokyo)

 

Abstract :

F1-ATPase is a rotary motor protein in which the inner subunit rotates against the

surrounding stator ring upon ATP hydrolysis(1,2). The stator ring is composed of

3 alpha and 3 beta subunits, and the catalytic reaction centers are located on the

3 alpha-beta interfaces, mainly on the beta subunits. The unique feature of F1-ATPase

that discriminates it from other molecular motors is the high energy conversion efficiency

and the reversibility of the chemomechanical coupling; when the rotation is forcibly

reversed, F1-ATPase catalyzes ATP synthesis reaction against large free energy of

ATP hydrolysis (3). The experimental verification that the rotary angle of the rotary shaft

controls the chemical equilibrium of ATP hydrolysis/synthesis was thought to suggest

that the 3 reaction centers communicate via the atomically fine-tuned molecular interaction

of the beta subunits with the rotary shaft subunit. However, recent experiments showed

the rotation mechanism is far more robust than we though before; even after removing

the rotary shaft, the remaining stator ring undergoes cooperative power stroke motion among

3 beta subunits (4). This finding suggests that the allostery is programmed in the stator ring,

pointing the possibility that an artificial rod-shaped molecule would be rotated in the

stator ring of F1-ATPase.

We tested this hypothesis by incorporating a xenogeneic protein in the stator ring.

The artificial molecule showed unidirectional rotation although the generated torque is

evidently lower than the wild-type F1-ATPase(5).

 

 1. Noji, H., Yasuda, R., Yoshida, M., and Kinosita, K., Jr. (1997) Direct observation

    of the rotation of F1-ATPase. Nature 386, 299-302

 2. Okuno, D., Iino, R., and Noji, H. (2011) Rotation and structure of FoF1-ATP synthase.

    Journal of biochemistry 149, 655-664

 3. Rondelez, Y., Tresset, G., Nakashima, T., Kato-Yamada, Y., Fujita, H., Takeuchi, S.,

    and Noji, H. (2005) Highly coupled ATP synthesis by F1-ATPase single molecules.

    Nature 433, 773-777

 4. Uchihashi, T., Iino, R., Ando, T., and Noji, H. (2011) High-speed atomic force

     microscopy reveals rotary catalysis of rotorless F(1)-ATPase. Science 333, 755-758

 5. Baba, M., Iwamoto, K., Iino, R., Ueno, H., Hara, M., Nakanishi, A., Kishikawa, J. I.,

     Noji, H., and Yokoyama, K. (2016) Rotation of artificial rotor axles in rotary molecular

     motors. Proceedings of the National Academy of Sciences of the United States of

     America 113, 11214-11219

 

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