Dilated cardiomyopathy mutation E525K in human beta-cardiac myosin stabilizes the interacting-heads motif and super-relaxed state of myosin.

Autor:	Rasicci DV; Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, United States., Tiwari P; Department of Radiology, Division of Cell Biology and Imaging, UMass Chan Medical School, Worcester, United States., Bodt SML; Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, United States., Desetty R; Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, United States., Sadler FR; Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, United States., Sivaramakrishnan S; Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, United States., Craig R; Department of Radiology, Division of Cell Biology and Imaging, UMass Chan Medical School, Worcester, United States., Yengo CM; Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, United States.
Jazyk:	angličtina
Zdroj:	ELife [Elife] 2022 Nov 24; Vol. 11. Date of Electronic Publication: 2022 Nov 24.
DOI:	10.7554/eLife.77415
Abstrakt:	The auto-inhibited, super-relaxed (SRX) state of cardiac myosin is thought to be crucial for regulating contraction, relaxation, and energy conservation in the heart. We used single ATP turnover experiments to demonstrate that a dilated cardiomyopathy (DCM) mutation (E525K) in human beta-cardiac myosin increases the fraction of myosin heads in the SRX state (with slow ATP turnover), especially in physiological ionic strength conditions. We also utilized FRET between a C-terminal GFP tag on the myosin tail and Cy3ATP bound to the active site of the motor domain to estimate the fraction of heads in the closed, interacting-heads motif (IHM); we found a strong correlation between the IHM and SRX state. Negative stain electron microscopy and 2D class averaging of the construct demonstrated that the E525K mutation increased the fraction of molecules adopting the IHM. Overall, our results demonstrate that the E525K DCM mutation may reduce muscle force and power by stabilizing the auto-inhibited SRX state. Our studies also provide direct evidence for a correlation between the SRX biochemical state and the IHM structural state in cardiac muscle myosin. Furthermore, the E525 residue may be implicated in crucial electrostatic interactions that modulate this conserved, auto-inhibited conformation of myosin. Competing Interests: DR, PT, SB, RD, FS, SS, RC, CY No competing interests declared (© 2022, Rasicci et al.)
Databáze:	MEDLINE
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