Article abstract


Nature Structural & Molecular Biology 14, 968 - 973 (2007)
Published online: 23 September 2007 | doi:10.1038/nsmb1298

Myosin-V makes two brownian 90° rotations per 36-nm step

Yasunori Komori1,2, Atsuko H Iwane1,3 & Toshio Yanagida1,2,3,4


Myosin-V processively walks on actin filaments in a hand-over-hand fashion. The identical structures of the heads predict a symmetric hand-over-hand mechanism where regular, unidirectional rotation occurs during a 36-nm step. We investigated this by observing how fixed myosin-V rotates actin filaments. Actin filaments randomly rotated 90° both clockwise and counter-clockwise during each step. Furthermore, ATP-dependent rotations were regularly followed by ATP-independent ones. Kinetic analysis indicated that the two 90° rotations relate to the coordinated unbinding and rebinding of the heads with actin. We propose a 'brownian rotation hand-over-hand' model, in which myosin-V randomly rotates by thermally twisting its elastic neck domains during the 36-nm step. The brownian rotation may be advantageous for cargo transport through a crowded actin meshwork and for carrying cargoes reliably via multiple myosin-V molecules in the cell.

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  1. Laboratories for Nanobiology, Graduate School of Frontier Biosciences, Osaka University, 1-3, Yamadaoka, Suita, Osaka, 565-0871, Japan.
  2. Formation of Soft Nano-Machines, Core Research for Evolutional Science and Technology, Japanese Science and Technology Corporation, 1-3, Yamadaoka, Suita, Osaka 565-0871, Japan.
  3. Department of Physiology and Biosignaling, Graduate School of Medicine, Osaka University, 2-2, Yamadaoka, Suita, Osaka, 565-0871, Japan.
  4. Special Coordination Funds for Promoting Science and Technology: Yuragi Project of the Ministry of Education, Culture, Sports, Science and Technology, 2-5-1, Marunouchi, Chiyoda-ku, Tokyo, 100-8959, Japan.

Correspondence to: Toshio Yanagida1,2,3,4 e-mail: yanagida@phys1.med.osaka-u.ac.jp



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