Overlapping hand-over-hand mechanism of single molecular motility of cytoplasmic dynein

doi:10.1073/pnas.0508511103

Overlapping hand-over-hand mechanism of single molecular motility of cytoplasmic dynein

*Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan; and
^‡Biomedical and Engineering Research Organization, Engineering Research Laboratory Complex 901, Tohoku University, 6-6-11 Aramaki, Sendai 980-8579, Japan

Edited by James A. Spudich, Stanford University School of Medicine, Stanford, CA, and approved February 11, 2006 (received for review September 29, 2005)

Abstract

Structural differences between dynein and kinesin suggest a unique molecular mechanism of dynein motility. Measuring the mechanical properties of a single molecule of dynein is crucial for revealing the mechanisms underlying its movement. We measured the step size and force produced by single molecules of active cytoplasmic dynein by using an optical trap and fluorescence imaging with a high temporal resolution. The velocity of dynein movement, 800 nm/s, is consistent with that reported in cells. The maximum force of 7–8 pN was independent of the ATP concentration and similar to that of kinesin. Dynein exhibited forward and occasional backwards steps of ≈8 nm, independent of load. It is suggested that the large dynein heads take 16-nm steps by using an overlapping hand-over-hand mechanism.

Footnotes

^§To whom correspondence should be addressed. E-mail: higuchi{at}tubero.tohoku.ac.jp
↵ ^†Present address: Kansai Advanced Research Center, National Institute of Information and Communications Technology, Kobe, Hyogo 651-2492, Japan.
Author contributions: S.T., Y.Y.T., and H.H. designed research; S.T., T.M.W., L.Y.-O., Y.Y.T., and H.H. performed research; S.T. and H.H. contributed new reagents/analytic tools; S.T., T.M.W., L.Y.-O., Y.Y.T., and H.H. analyzed data; and S.T., Y.Y.T., and H.H. wrote the paper.
Conflict of interest statement: No conflicts declared.
This paper was submitted directly (Track II) to the PNAS office.
Freely available online through the PNAS open access option.