Conserved mechanisms of microtubule-stimulated ADP release, ATP binding, and force generation in transport kinesins
- Birkbeck College, University of London, United Kingdom
- Institut Curie, Centre National de la Recherche Scientifique, France
- Lerner Research Institute, Cleveland Clinic, United States
Abstract
Kinesins are a superfamily of microtubule-based ATP-powered motors, important for multiple, essential cellular functions. How microtubule binding stimulates their ATPase and controls force generation is not understood. To address this fundamental question, we visualized microtubule-bound kinesin-1 and kinesin-3 motor domains at multiple steps in their ATPase cycles - including their nucleotide-free states - at ~7Å resolution using cryo-electron microscopy. In both motors, microtubule binding promotes ordered conformations of conserved loops that stimulate ADP release, enhance microtubule affinity and prime the catalytic site for ATP binding. ATP binding causes only small shifts of these nucleotide-coordinating loops but induces large conformational changes elsewhere that allow force generation and neck linker docking towards the microtubule plus end. Family-specific differences across the kinesin-microtubule interface account for the distinctive properties of each motor. Our data thus provide evidence for a conserved ATP-driven mechanism for kinesins and reveal the critical mechanistic contribution of the microtubule interface.
Article and author information
Author details
Copyright
© 2014, Atherton et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 4,092
- views
-
- 563
- downloads
-
- 108
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Conserved mechanisms of microtubule-stimulated ADP release, ATP binding, and force generation in transport kinesins
eLife 3:e03680.
https://doi.org/10.7554/eLife.03680
Further reading
-
- Biochemistry and Chemical Biology
- Structural Biology and Molecular Biophysics
Nature has inspired the design of improved inhibitors for cancer-causing proteins.
-
- Structural Biology and Molecular Biophysics
Transition-state (TS) theory has provided the theoretical framework to explain the enormous rate accelerations of chemical reactions by enzymes. Given that proteins display large ensembles of conformations, unique TSs would pose a huge entropic bottleneck for enzyme catalysis. To shed light on this question, we studied the nature of the enzymatic TS for the phosphoryl-transfer step in adenylate kinase by quantum-mechanics/molecular-mechanics calculations. We find a structurally wide set of energetically equivalent configurations that lie along the reaction coordinate and hence a broad transition-state ensemble (TSE). A conformationally delocalized ensemble, including asymmetric TSs, is rooted in the macroscopic nature of the enzyme. The computational results are buttressed by enzyme kinetics experiments that confirm the decrease of the entropy of activation predicted from such wide TSE. TSEs as a key for efficient enzyme catalysis further boosts a unifying concept for protein folding and conformational transitions underlying protein function.
