1AP4

REGULATORY DOMAIN OF HUMAN CARDIAC TROPONIN C IN THE CALCIUM-SATURATED STATE, NMR, 40 STRUCTURES

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 43 
  • Conformers Submitted: 40 
  • Selection Criteria: LEAST RESTRAINT VIOLATION 

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This is version 1.3 of the entry. See complete history. 


Literature

Calcium-induced structural transition in the regulatory domain of human cardiac troponin C.

Spyracopoulos, L., Li, M.X., Sia, S.K., Gagne, S.M., Chandra, M., Solaro, R.J., Sykes, B.D.

(1997) Biochemistry 36: 12138-12146

  • DOI: 10.1021/bi971223d
  • Primary Citation of Related Structures:  
    1AP4, 1SPY

  • PubMed Abstract: 

    • While calcium binding to troponin C (TnC) triggers the contraction of both skeletal and cardiac muscle, there is clear evidence that different mechanisms may be involved. For example, activation of heart myofilaments occurs with binding to a single regulatory site on TnC, whereas activation of fast skeletal myofilaments occurs with binding to two regulatory sites ...

    While calcium binding to troponin C (TnC) triggers the contraction of both skeletal and cardiac muscle, there is clear evidence that different mechanisms may be involved. For example, activation of heart myofilaments occurs with binding to a single regulatory site on TnC, whereas activation of fast skeletal myofilaments occurs with binding to two regulatory sites. The physiological difference between activation of cardiac and skeletal myofilaments is not understood at the molecular level due to a lack of structural details for the response of cardiac TnC to calcium. We determined the solution structures of the apo and calcium-saturated regulatory domain of human cardiac TnC by using multinuclear, multidimensional nuclear magnetic resonance spectroscopy. The structure of apo human cardiac TnC is very similar to that of apo turkey skeletal TnC even though there are critical amino acid substitutions in site I. In contrast to the case with the skeletal protein, the calcium-induced conformational transition in the cardiac regulatory domain does not involve an "opening" of the regulatory domain, and the concomitant exposure of a substantial hydrophobic surface area. This result has important implications with regard to potential unique aspects of the interaction of cardiac TnC with cardiac troponin I and of modification of cardiac myofilament regulation by calcium-sensitizer drugs.

    Organizational Affiliation: 

    MRC Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Canada.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CARDIAC N-TROPONIN CA89Homo sapiensMutation(s): 0 
Gene Names: TNNC1, TNNC
UniProt & NIH Common Fund Data Resources
Find proteins for P63316 (Homo sapiens)
Explore P63316 
Go to UniProtKB:  P63316
PHAROS:  P63316
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP63316
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA
Download Ideal Coordinates CCD File 
B [auth A]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 43 
  • Conformers Submitted: 40 
  • Selection Criteria: LEAST RESTRAINT VIOLATION 
  • OLDERADO: 1AP4 Olderado

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-07-15
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-02-16
    Changes: Database references, Derived calculations, Other