PDBsum entry 2jxl

Go to PDB code: 
protein metals links
Structural protein PDB id
Protein chain
89 a.a. *
* Residue conservation analysis
PDB id:
Name: Structural protein
Title: Solution structure of cardiac n-domain troponin c mutant f77w-v82a
Structure: Troponin c, slow skeletal and cardiac muscles. Chain: a. Fragment: regulatory domain. Synonym: tn-c. Engineered: yes. Mutation: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: tnnc1, tnnc. Expressed in: escherichia coli. Expression_system_taxid: 562.
NMR struc: 30 models
Authors: O.Julien,Y.Sun,X.Wang,D.A.Lindhout,A.Thiessen,M.Irving, B.D.Sykes
Key ref: O.Julien et al. (2008). Tryptophan mutants of cardiac troponin C: 3D structure, troponin I affinity, and in situ activity. Biochemistry, 47, 597-606. PubMed id: 18092822 DOI: 10.1021/bi702056g
20-Nov-07     Release date:   04-Dec-07    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P63316  (TNNC1_HUMAN) -  Troponin C, slow skeletal and cardiac muscles
161 a.a.
89 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 2 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Biochemical function     calcium ion binding     1 term  


DOI no: 10.1021/bi702056g Biochemistry 47:597-606 (2008)
PubMed id: 18092822  
Tryptophan mutants of cardiac troponin C: 3D structure, troponin I affinity, and in situ activity.
O.Julien, Y.B.Sun, X.Wang, D.A.Lindhout, A.Thiessen, M.Irving, B.D.Sykes.
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.

Literature references that cite this PDB file's key reference

  PubMed id Reference
19472326 O.Julien, P.Mercier, M.L.Crane, and B.D.Sykes (2009).
The effect of the cosolvent trifluoroethanol on a tryptophan side chain orientation in the hydrophobic core of troponin C.
  Protein Sci, 18, 1165-1174.
PDB code: 2kgb
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB code is shown on the right.