View the Current Issue

Article

  • The EMBO Journal (2000) 19, 5308 - 5314
  • doi:10.1093/emboj/19.20.5308

Structural comparison of dimeric Eg5, Neurospora kinesin (Nkin) and Ncd head–Nkin neck chimera with conventional kinesin

Keiko Hirose1, Ulrike Henningsen2, Manfred Schliwa2, Chikashi Toyoshima3, Takashi Shimizu4, Maria Alonso5, Robert A. Cross5 and Linda A. Amos6

  1. National Institute of Advanced Interdisciplinary Research, Tsukuba 305-8562, Japan
  2. Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113, Japan
  3. National Institute of Bioscience and Human Technology, Tsukuba 305, Japan
  4. Adolf-Butenandt-Institüt Zellbiologie, Ludwig-Maximilians-Universität, München, Germany
  5. Marie Curie Research Institute, Oxted, Surrey, UK
  6. MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK

Correspondence to:

Linda A. Amos, E-mail: laa@mrc-lmb.cam.ac.uk

Received 20 March 2000; Accepted 18 August 2000; Revised 17 August 2000

Cryo-electron microscopy and 3D image reconstruction of microtubules saturated with kinesin dimers has shown one head bound to tubulin, the other free. The free head of rat kinesin sits on the top right of the bound head (with the microtubule oriented plus-end upwards) in the presence of 5'-adenylylimido-diphosphate (AMPPNP) and on the top left in nucleotide-free solutions. To understand the relevance of this movement, we investigated other dimeric plus-end-directed motors: Neurospora kinesin (Nkin); Eg5, a slow non-processive kinesin; and a chimera of Ncd heads attached to Nkin necks. In the AMPPNP (ATP-like) state, all dimers have the free head to the top right. In the absence of nucleotide, the free head of an Nkin dimer appears to occupy alternative positions to either side of the bound head. Despite having the Nkin neck, the free head of the chimera was only seen to the top right of the bound head. Eg5 also has the free head mostly to the top right. We suggest that processive movement may require kinesins to move their heads in alternative ways.

  • Keywords:

    • cryo-electron microscopy,
    • Eg5,
    • kinesin,
    • microtubules,
    • Ncd