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

Wei Dong Gao, Christopher I. Murray, Ye Tian, Xin Zhong, Jenna F. Dumond, Xiaoxu Shen, Brian A. Stanley, D. Brian Foster, David A. Wink, S. Bruce King, Jennifer Van Eyk, Nazareno Paolocci

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


Rationale: In the myocardium, redox/cysteine modification of proteins regulating Ca 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 (Fmax) and reducing the concentration of Ca for 50% activation (Ca50) 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 Fmax 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 sensitivity and force generation, respectively. Conclusions:: HNO exerts a direct effect on cardiac myofilament proteins increasing myofilament Ca 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.

Original languageEnglish (US)
Pages (from-to)1002-1011
Number of pages10
JournalCirculation research
Issue number8
StatePublished - Sep 2012


  • calcium
  • contractility
  • nitroxyl
  • oxidant signaling
  • oxidation
  • redox
  • redox switch

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine


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