Article
- The EMBO Journal (2004) 23, 2993 - 2999
- doi:10.1038/sj.emboj.7600306
Published online: 15 July 2004
Subject Categories:
Rapid double 8-nm steps by a kinesin mutant
Hideo Higuchi1, Christian Eric Bronner2, Hee-Won Park3 and Sharyn A Endow2
- Department of Metallurgy and Center for Interdisciplinary Research, Tohoku University, Sendai, Japan
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, USA
Correspondence to:
Sharyn A Endow, Department of Cell Biology, Duke University Medical Center, 438 Jones Building, Research Drive, Durham, NC 27710, USA. Tel.: +1 919 684 4311; Fax: +1 919 684 8090; E-mail: endow@duke.edu
Received 24 March 2004; Accepted 11 June 2004
Abstract
The mechanism by which conventional kinesin walks along microtubules is poorly understood, but may involve alternate binding to the microtubule and hydrolysis of ATP by the two heads. Here we report a single amino-acid change that affects stepping by the motor. Under low force or low ATP concentration, the motor moves by successive 8-nm steps in single-motor laser-trap assays, indicating that the mutation does not alter the basic mechanism of kinesin walking. Remarkably, under high force, the mutant motor takes successive 16-nm displacements that can be resolved into rapid double 8-nm steps with a short dwell between steps, followed by a longer dwell. The alternating short and long dwells under high force demonstrate that the motor stepping mechanism is inherently asymmetric, revealing an asymmetric phase in the kinesin walking cycle. Our findings support an asymmetric two-headed walking model for kinesin, with cooperative interactions between the two heads. The sensitivity of the 16-nm displacements to nucleotide and load raises the possibility that ADP release is a force-producing event of the kinesin cycle.
Keywords:
- double steps,
- kinesin,
- motor mutant,
- stepping mechanism
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated
NEWS AND VIEWS
Nature Cell Biology News and Views (01 Dec 2003)
Cell biology High-performance fungal motors
Nature News and Views (06 Dec 2001)
RESEARCH
Alternate fast and slow stepping of a heterodimeric kinesin molecule
Nature Cell Biology Letter (01 Dec 2003)
Nature Article (19 May 2005)
