2JXL

Solution structure of cardiac N-domain troponin C mutant F77W-V82A


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 30 
  • Selection Criteria: structures with the lowest RMSD 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Tryptophan Mutants of Cardiac Troponin C: 3D Structure, Troponin I Affinity, and in Situ Activity.

Julien, O.Sun, Y.B.Wang, X.Lindhout, D.A.Thiessen, A.Irving, M.Sykes, B.D.

(2008) Biochemistry 47: 597-606

  • DOI: 10.1021/bi702056g
  • Primary Citation of Related Structures:  
    2JXL

  • PubMed Abstract: 
  • In situ fluorescence/NMR spectroscopic approaches have been used to elucidate the structure, mobility, and domain orientations of troponin C in striated muscle. This led us to consider complementary approaches such as solid-state NMR spectroscopy. The biophysical properties of tryptophan and Trp-analogues, such as fluorotryptophan or hydroxytryptophan, are often exploited to probe protein structure and dynamics using solid-state NMR or fluorescence spectroscopy ...

    In situ fluorescence/NMR spectroscopic approaches have been used to elucidate the structure, mobility, and domain orientations of troponin C in striated muscle. This led us to consider complementary approaches such as solid-state NMR spectroscopy. The biophysical properties of tryptophan and Trp-analogues, such as fluorotryptophan or hydroxytryptophan, are often exploited to probe protein structure and dynamics using solid-state NMR or fluorescence spectroscopy. We have characterized Phe-to-Trp mutants in the 'structural' C-domain of cardiac troponin C, designed to immobilize the indole ring in the hydrophobic core of the domain. The mutations and their fluorinated analogues (F104W, F104(5fW), F153W, and F153(5fW)) were shown not to perturb the structural properties of the protein. In this paper, we characterize the mutations F77W and F77W-V82A in the 'regulatory' N-domain of cardiac troponin C. We used NMR to determine the structure and dynamics of the mutant F77W-V82A-cNTnC, which shows a unique orientation of the indole ring. We observed a decrease in calcium binding affinity and a weaker affinity for the switch region of TnI for both mutants. We present force recovery measurements for all of the N- and C-domain mutants reconstituted into skeletal muscle fibers. The F77W mutation leads to a reduction of the in situ force recovery, whereas the C-domain mutants have the same activity as the wild type. These results suggest that the perturbations of the N-domain caused by the Trp mutation disturb the interaction between TnC and TnI, which in turn diminishes the activity in fibers, providing a clear example of the correlation between in vitro protein structures, their interactions, and the resulting in situ physiological activity.


    Organizational Affiliation

    Department of Biochemistry, University of Alberta, Edmonton, Canada.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin C, slow skeletal and cardiac muscles A89Homo sapiensMutation(s): 2 
Gene Names: TNNC1TNNC
Find proteins for P63316 (Homo sapiens)
Explore P63316 
Go to UniProtKB:  P63316
NIH Common Fund Data Resources
PHAROS:  P63316
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 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 30 
  • Selection Criteria: structures with the lowest RMSD 
  • OLDERADO: 2JXL Olderado

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-12-04
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance