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New Cardiology Findings from Mayo Clinic Described (Ventricular myosin modifies in vitro step-size when phosphorylated)

July 7, 2014

By a News Reporter-Staff News Editor at Cardiovascular Week -- Current study results on Cardiology have been published. According to news originating from Rochester, Minnesota, by NewsRx correspondents, research stated, "Cardiac and skeletal muscle myosins have the central role in contraction transducing ATP free energy into the mechanical work of moving actin. Myosin has a motor domain containing ATP and actin binding sites and a lever-arm that undergoes rotation impelling bound actin."

Our news journalists obtained a quote from the research from Mayo Clinic, "The lever-arm converts torque generated in the motor into the linear displacement known as step-size. The myosin lever-arm is stabilized by bound essential and regulatory light chains (ELC and RLC). RLC phosphorylation at S15 is linked to modified lever-arm mechanical characteristics contributing to myosin filament based contraction regulation and to the response of the muscle to disease. Myosin step-size was measured using a novel quantum dot (Qdot) assay that previously confirmed a 5 nm step-size for fast skeletal myosin and multiple unitary steps, most frequently 5 and 8 nm, and a rare 3 nm displacement for beta cardiac myosin (beta Mys). S15 phosphorylation in beta Mys is now shown to change stepsize distribution by advancing the 8 nm step frequency. After phosphorylation, the 8 nm step is the dominant myosin step-size resulting in significant gain in the average step-size. An increase in myosin step-size will increase the amount of work produced per ATPase cycle."

According to the news editors, the research concluded: "The results indicate that RLC phosphorylation modulates work production per ATPase cycle suggesting the mechanism for contraction regulation by the myosin filament."

For more information on this research see: Ventricular myosin modifies in vitro step-size when phosphorylated. Journal of Molecular and Cellular Cardiology, 2014;72():231-237. Journal of Molecular and Cellular Cardiology can be contacted at: Academic Press Ltd- Elsevier Science Ltd, 24-28 Oval Rd, London NW1 7DX, England. (Elsevier -; Journal of Molecular and Cellular Cardiology -

The news correspondents report that additional information may be obtained from Y.H. Wang, Mayo Clinic, Rochester, MN 55905, United States. Additional authors for this research include K. Ajtai and T.P. Burghardt (see also Cardiology).

Keywords for this news article include: ATPase, Rochester, Minnesota, Cardiology, Biopolymers, United States, Cardiac Myosins, Muscle Proteins, Ventricular Myosins, Contractile Proteins, Cytoskeletal Proteins, Enzymes and Coenzymes, Microfilament Proteins, North and Central America

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Source: Cardiovascular Week

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