Nitroxyl-mediated disulfide bond formation between cardiac myofilament cysteines enhances contractile function

Circ Res. 2012 Sep 28;111(8):1002-11. doi: 10.1161/CIRCRESAHA.112.270827. Epub 2012 Jul 31.


Rationale: In the myocardium, redox/cysteine modification of proteins regulating Ca(2+) cycling can affect contraction and may have therapeutic value. Nitroxyl (HNO), the one-electron-reduced form of nitric oxide, enhances cardiac function in a manner that suggests reversible cysteine modifications of the contractile machinery.

Objective: To determine the effects of HNO modification in cardiac myofilament proteins.

Methods and results: The HNO-donor, 1-nitrosocyclohexyl acetate, was found to act directly on the myofilament proteins, increasing maximum force (F(max)) and reducing the concentration of Ca(2+) for 50% activation (Ca(50)) in intact and skinned cardiac muscles. The effects of 1-nitrosocyclohexyl acetate are reversible by reducing agents and distinct from those of another HNO donor, Angeli salt, which was previously reported to increase F(max) without affecting Ca50. Using a new mass spectrometry capture technique based on the biotin switch assay, we identified and characterized the formation by HNO of a disulfide-linked actin-tropomyosin and myosin heavy chain-myosin light chain 1. Comparison of the 1-nitrosocyclohexyl acetate and Angeli salt effects with the modifications induced by each donor indicated the actin-tropomyosin and myosin heavy chain-myosin light chain 1 interactions independently correlated with increased Ca(2+) sensitivity and force generation, respectively.

Conclusions: HNO exerts a direct effect on cardiac myofilament proteins increasing myofilament Ca(2+) responsiveness by promoting disulfide bond formation between critical cysteine residues. These findings indicate a novel, redox-based modulation of the contractile apparatus, which positively impacts myocardial function, providing further mechanistic insight for HNO as a therapeutic agent.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / metabolism
  • Acetates / pharmacology
  • Actins / chemistry
  • Actins / metabolism
  • Animals
  • Calcium / metabolism
  • Cysteine / chemistry
  • Cysteine / metabolism
  • Dimerization
  • Disulfides / chemistry
  • Disulfides / metabolism*
  • Heart Failure / metabolism
  • Heart Failure / physiopathology
  • In Vitro Techniques
  • Muscle Fibers, Skeletal / cytology
  • Muscle Fibers, Skeletal / drug effects
  • Muscle Fibers, Skeletal / physiology
  • Muscle Proteins / chemistry
  • Muscle Proteins / metabolism
  • Myocardial Contraction / drug effects
  • Myocardial Contraction / physiology*
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / physiology*
  • Myofibrils / drug effects
  • Myofibrils / physiology*
  • Myosin Light Chains / chemistry
  • Myosin Light Chains / metabolism
  • Nitric Oxide / metabolism
  • Nitrogen Oxides / chemistry
  • Nitrogen Oxides / metabolism*
  • Nitroso Compounds / metabolism
  • Nitroso Compounds / pharmacology
  • Oxidation-Reduction
  • Rats


  • 1-nitrosocyclohexyl acetate
  • Acetates
  • Actins
  • Disulfides
  • Muscle Proteins
  • Myosin Light Chains
  • Nitrogen Oxides
  • Nitroso Compounds
  • myosin light chain I
  • Nitric Oxide
  • nitroxyl
  • Cysteine
  • Calcium