Dynamics of protein motors -From single molecules to systems

Shin'ichi Ishiwata


Department of Physics, School of Science and Engineering, Waseda University,
3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
E-mail: Ishiwata@mn.waseda.ac.jp

Abstract
I plan to talk about, occasionally showing video movies, 1) single molecular
mechanics of an actomyosin complex1 and a kinesin-microtubule complex2,3,
especially, on the binding force (the relationship between the force externally
imposed and the binding lifetime) under several nucleotide states, 2) several
characteristics of molecular motors such as temperature dependence4 and
torque production5,6, 3) polymerization-depolymerization dynamics of individual
actin filaments7 and 4) spontaneous oscillatory contraction of the contractile
apparatus8 and synchronization of sarcomere length oscillation with external
mechanical impulse (unpublished results). Here, I will emphasize that the
molecular synchronization occurs not only within single molecules (kinesin
motors) but also in a contractile system composed of many actomyosin motors
through mechano-chemical coupling.

Ref. 1) Nishizaka, T. et al. (1995) Nature, 377, 251-254. & (2000) Biophys. J. 79,
962-974. 2) Kawaguchi, K. and Ishiwata, S. (2001) Science, 291, 667-669. 3)
Uemura, S. et al. (2002) Proc. Natl. Acad. Sci. USA in press. 4) Kato, H. et al.
(1999) Proc. Natl. Acad. Sci. USA 96, 9602-9606, 5) Nishizaka, T. et al. (1993)
Nature 361, 269-271. 6) Sase, I. et al. (1997) Proc. Natl. Acad. Sci. USA. 94,
5646-5650. 7) Ishiwata, S. et al. (2001) In Molecular Interactions of Actin. (eds.
C.G. dos Remedios & D.D. Thomas) Springer-Verlag, Heidelberg, pp. 79-94. 8)
Yasuda, K. et al. (1996) Biophys. J. 70, 1823-1829.