Macromolecule Content

• Total Structure Weight: 18.43 kDa 
• Atom Count: 1275 
• Residue Count: 160 
• Unique protein chains: 1

1AJ4

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

• DOI: 10.2210/pdb1AJ4/pdb

• Classification: MUSCLE PROTEIN
• Organism(s): Gallus gallus
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 1997-05-14 Released: 1998-05-20 
• Deposition Author(s): Sia, S.K., Li, M.X., Spyracopoulos, L., Gagne, S.M., Liu, W., Putkey, J.A., Sykes, B.D.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 35 
• Conformers Submitted: 1 
• Selection Criteria: SMALLEST RMSD TO THE AVERAGE STRUCTURE 

Literature

Structure of cardiac muscle troponin C unexpectedly reveals a closed regulatory domain.

Sia, S.K., Li, M.X., Spyracopoulos, L., Gagne, S.M., Liu, W., Putkey, J.A., Sykes, B.D.

(1997) J Biol Chem 272: 18216-18221

• PubMed: 9218458 
• DOI: 10.1074/jbc.272.29.18216
• Structures With Same Primary Citation


• 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.

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Organizational Affiliation: 

Department of Biochemistry, Medical Research Council Group in Protein Structure and Function, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
TROPONIN C	A	161	Gallus gallus	Mutation(s): 2  Gene Names: CTNC(A-CYS), TNNC1
Find proteins for P09860 (Gallus gallus) Go to UniProtKB:  P09860

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	A	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 35 
• Conformers Submitted: 1 
• Selection Criteria: SMALLEST RMSD TO THE AVERAGE STRUCTURE 
• OLDERADO: 1AJ4 Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1997-05-14 
• Released Date: 1998-05-20 
Deposition Author(s): Sia, S.K., Li, M.X., Spyracopoulos, L., Gagne, S.M., Liu, W., Putkey, J.A., Sykes, B.D.

Revision History 

• Version 1.0: 1998-05-20
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance