1AJ4

STRUCTURE OF CALCIUM-SATURATED CARDIAC TROPONIN C, NMR, 1 STRUCTURE

Summary for 1AJ4

• Entry DOI: 10.2210/pdb1aj4/pdb
• Descriptor: TROPONIN C, CALCIUM ION (2 entities in total)
• Functional Keywords: cardiac, muscle protein, regulatory, calcium binding
• Biological source: Gallus gallus (chicken)
• Total number of polymer chains: 1
• Total formula weight: 18431.51

Authors

Sia, S.K.,Li, M.X.,Spyracopoulos, L.,Gagne, S.M.,Liu, W.,Putkey, J.A.,Sykes, B.D. (deposition date: 1997-05-14, release date: 1998-05-20, Last modification date: 2024-05-22)

Primary citation

Sia, S.K.,Li, M.X.,Spyracopoulos, L.,Gagne, S.M.,Liu, W.,Putkey, J.A.,Sykes, B.D.
Structure of cardiac muscle troponin C unexpectedly reveals a closed regulatory domain.
J.Biol.Chem., 272:18216-18221, 1997

PubMed Abstract: The 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.

PubMed: 9218458
DOI: 10.1074/jbc.272.29.18216

Experimental method

SOLUTION NMR