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Kinesin's second step
- *Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260; and ‡European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69012 Heidelberg, Germany
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Edited by Thomas D. Pollard, Yale University, New Haven, CT (received for review November 21, 2003)
Abstract
We have identified dimeric kinesin mutants that become stalled on the microtubule after one ATP turnover, unable to bind and hydrolyze ATP at their second site. We have used these mutants to determine the regulatory signal that allows ATP to bind to the forward head, such that processive movement can continue. The results show that phosphate release occurs from the rearward head before detachment, and detachment triggers active-site accessibility for ATP binding at the forward head. This mechanism, in which the rearward head controls the behavior of the forward head, may be conserved among processive motors.
Footnotes
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↵ § To whom correspondence should be addressed at: Department of Biological Sciences, 518 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260. E-mail: spg1{at}pitt.edu.
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↵ † Present address: Department of Pharmacology, University of Pennsylvania School of Medicine, 131 John Morgan Building, 3610 Hamilton Walk, Philadelphia, PA 19104-6084.
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This paper was submitted directly (Track II) to the PNAS office.
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Abbreviations: K401/341, construct comprising the N-terminal 401/341 amino acids of Drosophila melanogaster; Mt, microtubule; mantATP/ADP, 2′(3′)-O-(N-methylanthraniloyl)-ATP/ADP; PBP, phosphate-binding protein; MDCC, N-[2-(1-maleimidyl)ethyl]-7-(diethylamino)coumarin-3-carboxamide; MEG, 7-methylguanosine; PNPase, bacterial purine nucleoside phosphorylase.
- Copyright © 2004, The National Academy of Sciences
