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Cardiac myosin activation with 2-deoxy-ATP via increased electrostatic interactions with actin.

Abstract

The naturally occurring nucleotide 2-deoxy-adenosine 5'-triphosphate (dATP) can be used by cardiac muscle as an alternative energy substrate for myosin chemomechanical activity. We and others have previously shown that dATP increases contractile force in normal hearts and models of depressed systolic function, but the structural basis of these effects has remained unresolved. In this work, we combine multiple techniques to provide structural and functional information at the angstrom-nanometer and millisecond time scales, demonstrating the ability to make both structural measurements and quantitative kinetic estimates of weak actin-myosin interactions that underpin sarcomere dynamics. Exploiting dATP as a molecular probe, we assess how small changes in myosin structure translate to electrostatic-based changes in sarcomere function to augment contractility in cardiac muscle. Through Brownian dynamics simulation and computational structural analysis, we found that deoxy-hydrolysis products [2-deoxy-adenosine 5'-diphosphate (dADP) and inorganic phosphate (Pi)] bound to prepowerstroke myosin induce an allosteric restructuring of the actin-binding surface on myosin to increase the rate of cross-bridge formation. We then show experimentally that this predicted effect translates into increased electrostatic interactions between actin and cardiac myosin in vitro. Finally, using small-angle X-ray diffraction analysis of sarcomere structure, we demonstrate that the proposed increased electrostatic affinity of myosin for actin causes a disruption of the resting conformation of myosin motors, resulting in their repositioning toward the thin filament before activation. The dATP-mediated structural alterations in myosin reported here may provide insight into an improved criterion for the design or selection of small molecules to be developed as therapeutic agents to treat systolic dysfunction.

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  • Authors+Show Affiliations

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    Department of Bioengineering, University of Washington, Seattle, WA 98109; j2powers@ucsd.edu mregnier@uw.edu. Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109. Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616.

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    Department of Bioengineering, University of Washington, Seattle, WA 98109.

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    Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093.

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    Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616.

    Department of Bioengineering, University of Washington, Seattle, WA 98109; j2powers@ucsd.edu mregnier@uw.edu. Department of Physiology and Biophysics, University of Washington, Seattle, WA 98109.

    Source

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    31110001

    Citation

    Powers, Joseph D., et al. "Cardiac Myosin Activation With 2-deoxy-ATP Via Increased Electrostatic Interactions With Actin." Proceedings of the National Academy of Sciences of the United States of America, vol. 116, no. 23, 2019, pp. 11502-11507.
    Powers JD, Yuan CC, McCabe KJ, et al. Cardiac myosin activation with 2-deoxy-ATP via increased electrostatic interactions with actin. Proc Natl Acad Sci USA. 2019;116(23):11502-11507.
    Powers, J. D., Yuan, C. C., McCabe, K. J., Murray, J. D., Childers, M. C., Flint, G. V., ... Regnier, M. (2019). Cardiac myosin activation with 2-deoxy-ATP via increased electrostatic interactions with actin. Proceedings of the National Academy of Sciences of the United States of America, 116(23), pp. 11502-11507. doi:10.1073/pnas.1905028116.
    Powers JD, et al. Cardiac Myosin Activation With 2-deoxy-ATP Via Increased Electrostatic Interactions With Actin. Proc Natl Acad Sci USA. 2019 Jun 4;116(23):11502-11507. PubMed PMID: 31110001.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Cardiac myosin activation with 2-deoxy-ATP via increased electrostatic interactions with actin. AU - Powers,Joseph D, AU - Yuan,Chen-Ching, AU - McCabe,Kimberly J, AU - Murray,Jason D, AU - Childers,Matthew Carter, AU - Flint,Galina V, AU - Moussavi-Harami,Farid, AU - Mohran,Saffie, AU - Castillo,Romi, AU - Zuzek,Carla, AU - Ma,Weikang, AU - Daggett,Valerie, AU - McCulloch,Andrew D, AU - Irving,Thomas C, AU - Regnier,Michael, Y1 - 2019/05/20/ PY - 2019/11/20/pmc-release PY - 2019/5/22/pubmed PY - 2019/5/22/medline PY - 2019/5/22/entrez KW - X-ray diffraction KW - dATP KW - electrostatics KW - myosin structure KW - sarcomere structure SP - 11502 EP - 11507 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc. Natl. Acad. Sci. U.S.A. VL - 116 IS - 23 N2 - The naturally occurring nucleotide 2-deoxy-adenosine 5'-triphosphate (dATP) can be used by cardiac muscle as an alternative energy substrate for myosin chemomechanical activity. We and others have previously shown that dATP increases contractile force in normal hearts and models of depressed systolic function, but the structural basis of these effects has remained unresolved. In this work, we combine multiple techniques to provide structural and functional information at the angstrom-nanometer and millisecond time scales, demonstrating the ability to make both structural measurements and quantitative kinetic estimates of weak actin-myosin interactions that underpin sarcomere dynamics. Exploiting dATP as a molecular probe, we assess how small changes in myosin structure translate to electrostatic-based changes in sarcomere function to augment contractility in cardiac muscle. Through Brownian dynamics simulation and computational structural analysis, we found that deoxy-hydrolysis products [2-deoxy-adenosine 5'-diphosphate (dADP) and inorganic phosphate (Pi)] bound to prepowerstroke myosin induce an allosteric restructuring of the actin-binding surface on myosin to increase the rate of cross-bridge formation. We then show experimentally that this predicted effect translates into increased electrostatic interactions between actin and cardiac myosin in vitro. Finally, using small-angle X-ray diffraction analysis of sarcomere structure, we demonstrate that the proposed increased electrostatic affinity of myosin for actin causes a disruption of the resting conformation of myosin motors, resulting in their repositioning toward the thin filament before activation. The dATP-mediated structural alterations in myosin reported here may provide insight into an improved criterion for the design or selection of small molecules to be developed as therapeutic agents to treat systolic dysfunction. SN - 1091-6490 UR - https://www.unboundmedicine.com/medline/citation/31110001/Cardiac_myosin_activation_with_2-deoxy-ATP_via_increased_electrostatic_interactions_with_actin L2 - http://www.pnas.org/cgi/pmidlookup?view=long&pmid=31110001 DB - PRIME DP - Unbound Medicine ER -