This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rice, S. Articles by Cooke, R. Search for Related Content PubMed PubMed Citation Articles by Rice, S. Articles by Cooke, R.

Thermodynamic Properties of the Kinesin Neck-Region Docking to the Catalytic Core

Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94143

Correspondence: Address reprint requests to Roger Cooke, University of California-San Francisco, Box 448, San Francisco, CA 94143-0448. Tel.: 514-476-4836; Fax: 415-476-1902; E-mail: cooke{at}cgl.ucsf.edu.

Kinesin motors move on microtubules by a mechanism that involves a large, ATP-triggered conformational change in which a mechanical element called the neck linker docks onto the catalytic core, making contacts with the core throughout its length. Here, we investigate the thermodynamic properties of this conformational change using electron paramagnetic resonance (EPR) spectroscopy. We placed spin probes at several locations on the human kinesin neck linker and recorded EPR spectra in the presence of microtubules and either 5'-adenylylimidodiphosphate (AMPPNP) or ADP at temperatures of 4–30°C. The free-energy change (G) associated with AMPPNP-induced docking of the neck linker onto the catalytic core is favorable but small, about 3 kJ/mol. In contrast, the favorable enthalpy change (H) and unfavorable entropy change (TS) are quite large, about 50 kJ/mol. A mutation in the neck linker, V331A/N332A, results in an unfavorable G for AMPPNP-induced zipping of the neck linker onto the core and causes motility defects. These results suggest that the kinesin neck linker folds onto the core from a more unstructured state, thereby paying a large entropic cost and gaining a large amount of enthalpy.

This article has been cited by other articles:

				Z. Wang, M. Feng, W. Zheng, and D. Fan Kinesin Is an Evolutionarily Fine-Tuned Molecular Ratchet-and-Pawl Device of Decisively Locked Direction Biophys. J., November 15, 2007; 93(10): 3363 - 3372. [Abstract] [Full Text] [PDF]

				S. M. Block Kinesin Motor Mechanics: Binding, Stepping, Tracking, Gating, and Limping Biophys. J., May 1, 2007; 92(9): 2986 - 2995. [Full Text] [PDF]

				N. Naber, T. J. Purcell, E. Pate, and R. Cooke Dynamics of the Nucleotide Pocket of Myosin Measured by Spin-Labeled Nucleotides Biophys. J., January 1, 2007; 92(1): 172 - 184. [Abstract] [Full Text] [PDF]

				W. H. Mather and R. F. Fox Kinesin's Biased Stepping Mechanism: Amplification of Neck Linker Zippering Biophys. J., October 1, 2006; 91(7): 2416 - 2426. [Abstract] [Full Text] [PDF]

				K. Hahlen, B. Ebbing, J. Reinders, J. Mergler, A. Sickmann, and G. Woehlke Feedback of the Kinesin-1 Neck-linker Position on the Catalytic Site J. Biol. Chem., July 7, 2006; 281(27): 18868 - 18877. [Abstract] [Full Text] [PDF]

				S. S. Rosenfeld, J. Xing, G. M. Jefferson, and P. H. King Docking and Rolling, a Model of How the Mitotic Motor Eg5 Works J. Biol. Chem., October 21, 2005; 280(42): 35684 - 35695. [Abstract] [Full Text] [PDF]

				R. Cooke The Sliding Filament Model: 1972-2004 J. Gen. Physiol., June 1, 2004; 123(6): 643 - 656. [Full Text] [PDF]

				M. Y. Ali, K. Homma, A. H. Iwane, K. Adachi, H. Itoh, K. Kinosita Jr., T. Yanagida, and M. Ikebe Unconstrained Steps of Myosin VI Appear Longest among Known Molecular Motors Biophys. J., June 1, 2004; 86(6): 3804 - 3810. [Abstract] [Full Text] [PDF]

				E. P. Sablin and R. J. Fletterick Coordination between Motor Domains in Processive Kinesins J. Biol. Chem., April 16, 2004; 279(16): 15707 - 15710. [Full Text] [PDF]