Mechanistic Insights into the Active Site and Allosteric Communication Pathways in Human Nonmuscle Myosin-2C
Abstract
Despite a generic, highly conserved motor domain, ATP turnover kinetics and their activation by F-actin vary greatly between myosin-2 isoforms. Here, we present a 2.25 Å crystal pre-powerstroke state (ADP·VO4) structure of the human nonmuscle myosin-2C motor domain, one of the slowest myosins characterized. In combination with integrated mutagenesis, ensemble-solution kinetics, and molecular dynamics simulation approaches, the structure reveals an allosteric communication pathway that connects the distal end of the motor domain with the active site. Disruption of this pathway by mutation of hub residue R788, which forms the center of a cluster of interactions connecting the converter, the SH1-SH2 helix, the relay helix, and the lever, abolishes nonmuscle myosin-2 specific kinetic signatures. Our results provide insights into structural changes in the myosin motor domain that are triggered upon F-actin binding and contribute critically to the mechanochemical behavior of stress fibers, actin arcs, and cortical actin-based structures.
Article and author information
Author details
Funding
Deutsche Forschungsgemeinschaft (MA 1081_21-1)
- Dietmar J Manstein
National Institutes of Health (Intramural Funding)
- James R Sellers
Deutsche Forschungsgemeinschaft (PR 1478_2-1)
- Matthias Preller
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Pekka Lappalainen, University of Helsinki, Finland
Version history
- Received: October 12, 2017
- Accepted: December 18, 2017
- Accepted Manuscript published: December 19, 2017 (version 1)
- Version of Record published: January 2, 2018 (version 2)
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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