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Nucleotide-Dependent Single- to Double-Headed Binding of Kinesin

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Science  26 Jan 2001:
Vol. 291, Issue 5504, pp. 667-669
DOI: 10.1126/science.291.5504.667

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Abstract

The motility of kinesin motors is explained by a “hand-over-hand” model in which two heads of kinesin alternately repeat single-headed and double-headed binding with a microtubule. To investigate the binding mode of kinesin at the key nucleotide states during adenosine 5′-triphosphate (ATP) hydrolysis, we measured the mechanical properties of a single kinesin-microtubule complex by applying an external load with optical tweezers. Both the unbinding force and the elastic modulus in solutions containing AMP-PNP (an ATP analog) were twice the value of those in nucleotide-free solution or in the presence of both AMP-PNP and adenosine 5′-diphosphate. Thus, kinesin binds through two heads in the former and one head in the latter two states, which supports a major prediction of the hand-over-hand model.

  • * To whom correspondence should be addressed. E-mail: ishiwata{at}mn.waseda.ac.jp

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