Structure of trans-Resveratrol in Complex with the Cardiac Regulatory Protein Troponin C

Abstract

Cardiac troponin -a heterotrimeric protein complex that regulates heart contraction -represents an attractive target for the development of drugs to treat heart disease. Cardiovascular diseases are one of the chief causes of morbidity and mortality worldwide. In France, however, the death rate from heart disease is remarkably low relative to fat consumption. This so called "French paradox" has been attributed to the high consumption of wine in France; and the antioxidant transresveratrol is thought to be the primary basis for wine's cardioprotective nature. It has been demonstrated that trans-resveratrol increases the myofilament Ca 2+ -sensitivity of guinea-pig myocytes (Liew, R., Stagg, M.A., MacLeod, K.T., and Collins, P., (2005) Eur. J. Pharmacol. 519,[1][2][3][4][5][6][7][8], however, the specific mode of its action is unknown. In this study, the structure of transresveratrol free and bound to the calcium-binding protein, troponin C, was determined by NMR spectroscopy. The results indicate that trans-resveratrol undergoes a minor conformational change upon binding to the hydrophobic pocket of the C-domain of troponin C. The location occupied by trans-resveratrol coincides with the binding site of troponin I -troponin C's natural binding partner. This has been seen for other troponin C-targeting inotropes and implicates the modulation of the troponin C-troponin I interaction as a possible mechanism of action for trans-resveratrol. KeywordsTrans-resveratrol; troponin C; NMR spectroscopy; cardiac muscle; contraction; Ca 2+ -sensitizerThe physiological function of the heart is to pump blood throughout the body in order to fulfill the oxygen and nutrient demands of the organism. The thin filament in heart muscle is made up of actin, tropomyosin, and troponin. Troponin is a heterotrimeric protein complex formed by the Ca 2+ -binding subunit, troponin C (TnC); the inhibitory subunit, troponin I (TnI); and the tropomyosin-binding subunit, troponin T (TnT). Cardiac TnC (cTnC) has four EF-hand metal binding sites (I-IV) -two in each of its terminal domains. The C-terminal (cCTnC) and N-terminal (cNTnC) domains are connected by a flexible linker, as shown by the NMR (1) and X-ray structures (2). In cNTnC, site I is defunct and site II is a low-affinity Ca 2+ -binding site; on the other hand, both site III and site IV in cCTnC are functional and can bind either Mg 2+ or Ca 2+ . During the contraction-relaxation cycle, cytosolic Ca 2+ concentration dramatically oscillates: at high Ca 2+ levels, cNTnC becomes Ca 2+ -saturated, * CORRESPONDING AUTHOR FOOTNOTE: Phone Number: (780) 492-5460, Fax Number: (780) 492-0886, brian.sykes@ualberta.ca. § Both authors contributed equally to this work. Supporting Information Available:Data illustrating the oxidation rate of resveratrol; the resveratrol ROE intensities versus mixing time; the binding of resveratrol to cTnC; the ligand dependant chemical shift perturbations of cCTnC; the intramolecular NOEs of resveratrol in complex with cCTnC; and the structural statistics for ...

Structure and function of cardiac troponin C (TNNC1): Implications for heart failure, cardiomyopathies, and troponin modulating drugs

“…The polyphenolic compounds EGCg 160 and resveratrol 161 were also found to bind to cCTnC, but not cNTnC. While EGCg is found in green tea, resveratrol is found in red wine.…”

“…While EGCg is found in green tea, resveratrol is found in red wine. The NMR solution structures of cCTnC•2Ca 2+ •EGCg 160 and cCTnC•2Ca 2+ •resveratrol 161 show that these compounds bind to a similar pocket as EMD 57033 (see Figure 7). EGCg binding is more shallow than EMD 57033 binding, and unlike EMD 57033, EGCg can still bind cCTnC in the presence cTnI 34–71 , although the affinity is very weak, with a K D of about 1.8 mM.…”

Sarcomere neutralization in inherited cardiomyopathy: small-molecule proof-of-concept to correct hyper-Ca2+-sensitive myofilaments

“…Whereas several small-molecule Ca 2ϩ sensitizers have been developed for the treatment of heart failure, little attention has been paid to myofilament Ca 2ϩ desensitizers. EGCG and resveratrol have been suggested to bind to cTnC and decrease Ca 2ϩ sensitivity (19,26,28). EGCG was recently shown to improve diastolic dysfunction in HCM and RCM mouse models, suggesting that desensitization of the myofilament is therapeutically relevant (10,32,35).…”

Resveratrol and polydatin as modulators of Ca2+mobilization in the cardiovascular system

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