Biased Binding of Single Molecules and Continuous Movement of Multiple Molecules of Truncated Single-Headed Kinesin
Takashi Kamei 1, Seiji Kakuta 2 and Hideo Higuchi 2*
1 Tohoku Univ.
2 Tohoku.Univ.
* To whom correspondence should be addressed. E-mail: higuchi{at}material.tohoku.ac.jp.
Submitted on July 15, 2004
Revised on August 24, 2004
Accepted on 27 December 2004
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Abstract |
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Conventional kinesin has a double-headed structure consisting of two motor domains and moves processively along a microtubule using the two heads cooperatively. The movement of single and multiple truncated-heads of Drosophila kinesin was measured using a laser trap and nanometer detecting apparatus. Single molecules of single-headed kinesin bound to the microtubules with a 3.5 nm biased displacement towards the plus end of the microtubule. The position of these single-headed kinesin molecules bound to a microtubule did not change until they had dissociated, indicating that single kinesin heads utilize non-processive movement processes. Two molecules of single-headed kinesin moved continuously along a microtubule with a lower velocity and force than that of single molecules of double-headed kinesin. The biased binding of the heads determines the directionality of movement, while two molecules of single-headed kinesin move continuously without dissociation from a microtubule.
Key Words:
Biased binding, Laser trap, Processive movement, Single molecule, Single-headed kinesin
