2KRD

Solution Structure of the Regulatory Domain of Human Cardiac Troponin C in Complex with the Switch Region of cardiac Troponin I and W7


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Solution structure of the regulatory domain of human cardiac troponin C in complex with the switch region of cardiac troponin I and W7: the basis of W7 as an inhibitor of cardiac muscle contraction.

Oleszczuk, M.Robertson, I.M.Li, M.X.Sykes, B.D.

(2010) J.MOL.CELL.CARDIOL. 48: 925-933

  • DOI: 10.1016/j.yjmcc.2010.01.016

  • PubMed Abstract: 
  • The solution structure of Ca(2+)-bound regulatory domain of cardiac troponin C (cNTnC) in complex with the switch region of troponin I (cTnI(147-163)) and the calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfinamide (W7), has been de ...

    The solution structure of Ca(2+)-bound regulatory domain of cardiac troponin C (cNTnC) in complex with the switch region of troponin I (cTnI(147-163)) and the calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfinamide (W7), has been determined by NMR spectroscopy. The structure reveals that the W7 naphthalene ring interacts with the terminal methyl groups of M47, M60, and M81 as well as aliphatic and aromatic side chains of several other residues in the hydrophobic pocket of cNTnC. The H3 ring proton of W7 also contacts the methyl groups of I148 and M153 of cTnI(147-163). The N-(6-aminohexyl) tail interacts primarily with the methyl groups of V64 and M81, which are located on the C- and D-helices of cNTnC. Compared to the structure of the cNTnC*Ca(2+)*W7 complex (Hoffman, R. M. B. and Sykes, B. D. (2009) Biochemistry 48, 5541-5552), the tail of W7 reorients slightly toward the surface of cNTnC while the ring remains in the hydrophobic pocket. The positively charged -NH(3)(+) group from the tail of W7 repels the positively charged R147 of cTnI(147-163). As a result, the N-terminus of the peptide moves away from cNTnC and the helical content of cTnI(147-163) is diminished, when compared to the structure of cNTnC*Ca(2+)*cTnI(147-163) (Li, M. X., Spyracopoulos, L., and Sykes B. D. (1999) Biochemistry 38, 8289-8298). Thus the ternary structure cNTnC*Ca(2+)*W7*cTnI(147-163) reported in this study offers an explanation for the approximately 13-fold affinity reduction of cTnI(147-163) for cNTnC*Ca(2+) in the presence of W7 and provides a structural basis for the inhibitory effect of W7 in cardiac muscle contraction. This generates molecular insight into structural features that are useful for the design of cTnC-specific Ca(2+)-desensitizing drugs.


    Organizational Affiliation

    Department of Biochemistry, School of Molecular and Systems Medicine, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Troponin C, slow skeletal and cardiac muscles
C
89Homo sapiensMutation(s): 0 
Gene Names: TNNC1 (TNNC)
Find proteins for P63316 (Homo sapiens)
Go to Gene View: TNNC1
Go to UniProtKB:  P63316
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Troponin I, cardiac muscle
I
17Homo sapiensMutation(s): 0 
Gene Names: TNNI3 (TNNC1)
Find proteins for P19429 (Homo sapiens)
Go to Gene View: TNNI3
Go to UniProtKB:  P19429
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
WW7
Query on WW7

Download SDF File 
Download CCD File 
I
N-(6-AMINOHEXYL)-5-CHLORO-1-NAPHTHALENESULFONAMIDE
C16 H21 Cl N2 O2 S
IDEHCMNLNCJQST-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

Download SDF File 
Download CCD File 
C
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 2KRD Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-02-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance