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STRUCTURE OF CALCIUM-SATURATED CARDIAC TROPONIN C, NMR, 1 STRUCTURE
Structural highlights
FunctionTNNC1_CHICK Troponin is the central regulatory protein of striated muscle contraction. Tn consists of three components: Tn-I which is the inhibitor of actomyosin ATPase, Tn-T which contains the binding site for tropomyosin and Tn-C. The binding of calcium to Tn-C abolishes the inhibitory action of Tn on actin filaments. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe regulation of cardiac muscle contraction must differ from that of skeletal muscles to effect different physiological and contractile properties. Cardiac troponin C (TnC), the key regulator of cardiac muscle contraction, possesses different functional and Ca2+-binding properties compared with skeletal TnC and features a Ca2+-binding site I, which is naturally inactive. The structure of cardiac TnC in the Ca2+-saturated state has been determined by nuclear magnetic resonance spectroscopy. The regulatory domain exists in a "closed" conformation even in the Ca2+-bound (the "on") state, in contrast to all predicted models and differing significantly from the calcium-induced structure observed in skeletal TnC. This structure in the Ca2+-bound state, and its subsequent interaction with troponin I (TnI), are crucial in determining the specific regulatory mechanism for cardiac muscle contraction. Further, it will allow for an understanding of the action of calcium-sensitizing drugs, which bind to cardiac TnC and are known to enhance the ability of cardiac TnC to activate cardiac muscle contraction. Structure of cardiac muscle troponin C unexpectedly reveals a closed regulatory domain.,Sia SK, Li MX, Spyracopoulos L, Gagne SM, Liu W, Putkey JA, Sykes BD J Biol Chem. 1997 Jul 18;272(29):18216-21. PMID:9218458[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
