Design principles governing chemomechanical coupling of kinesin
Tomonari Sumi
Scientific Reports 7, Article number: 1163 (2017)
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Biophysical chemistry Motor protein function Motor protein regulation
Received: 13 October 2016 Accepted: 28 March 2017 Published online: 25 April 2017
Source/Fonte - “ATP Synthase: The Power Plant of the Cell.”
Abstract
A systematic chemomechanical network model for the molecular motor kinesin is presented in this report. The network model is based on the nucleotide-dependent binding affinity of the heads to an microtubule (MT) and the asymmetries and similarities between the chemical transitions caused by the intramolecular strain between the front and rear heads. The network model allows for multiple chemomechanical cycles and takes into account all possible mechanical transitions between states in which one head is strongly bound and the other head is weakly bound to an MT. The results obtained from the model show the ATP-concentration dependence of the dominant forward stepping cycle and support a gated rear head mechanism in which the forward step is controlled by ATP hydrolysis and the resulting ADP-bound state of the rear head when the ATP level is saturated. When the ATP level is saturated, the energy from ATP hydrolysis is used to concentrate the chemical transition flux to a force-generating state that can produce the power stroke. In contrast, when the ATP level is low, the hydrolysis energy is consumed to avoid states in which the leading head is weakly bound to an MT and to inhibit frequent backward steps upon loading.
Acknowledgements
This work was supported by the Grants-in-Aid for Scientific Research (KAKENHI) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. I would like to thank Prof. Stefan Klumpp in Georg-August-Universität Göttingen for extensive discussion about the chemomechanical network modeling and an extension of the steady state balance condition. I would also like to thank Prof. Michio Tomishige in Tokyo University for useful discussions. I also thank Enago (www.enago.jp) for the English language review.
Author information
Affiliations
Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
Tomonari Sumi
Department of Chemistry, Faculty of Science, Okayama University, 3-1-1 Tsushima-Naka, Kita-ku, Okayama, 700-8530, Japan
Tomonari Sumi
Competing Interests
The authors declare that they have no competing interests.
Corresponding author
Correspondence to Tomonari Sumi.
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