PDBsum entry 2jt8

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protein links
Structural protein PDB id
Protein chain
161 a.a. *
* Residue conservation analysis
PDB id:
Name: Structural protein
Title: Solution structure of the f153-to-5-flurotryptophan mutant of human cardiac troponin c
Structure: Troponin c, slow skeletal and cardiac muscles. Chain: a. 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. Expression_system_variant: (de3)plyss.
NMR struc: 10 models
Authors: X.Wang,P.Mercier,P.Letourneau,B.D.Sykes
Key ref:
X.Wang et al. (2005). Effects of Phe-to-Trp mutation and fluorotryptophan incorporation on the solution structure of cardiac troponin C, and analysis of its suitability as a potential probe for in situ NMR studies. Protein Sci, 14, 2447-2460. PubMed id: 16131667 DOI: 10.1110/ps.051595805
20-Jul-07     Release date:   07-Aug-07    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P63316  (TNNC1_HUMAN) -  Troponin C, slow skeletal and cardiac muscles
161 a.a.
161 a.a.*
Key:    PfamA domain  Secondary structure  CATH domain
* PDB and UniProt seqs differ at 3 residue positions (black crosses)

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     cytosol   3 terms 
  Biological process     response to metal ion   8 terms 
  Biochemical function     protein binding     8 terms  


DOI no: 10.1110/ps.051595805 Protein Sci 14:2447-2460 (2005)
PubMed id: 16131667  
Effects of Phe-to-Trp mutation and fluorotryptophan incorporation on the solution structure of cardiac troponin C, and analysis of its suitability as a potential probe for in situ NMR studies.
X.Wang, P.Mercier, P.J.Letourneau, B.D.Sykes.
19F NMR spectroscopy is potentially a powerful tool for probing protein properties in situ. However, results obtained using this technique are relevant only if the 19F probe offers minimal perturbation to the surrounding environment. In this paper, we examine the effect of 5-fluorotryptophan (5fW) incorporation on the three-dimensional structure of cardiac troponin-C (cTnC), with the intention of developing a 19F-labeled TnC for use in in situ 19FNMR. We find that, in general, 5fW does not perturb the structure of the protein significantly. Replacement of residue Phe 153 with 5fW produces no noticeable change in protein conformation. However, replacement of residue Phe 104 with 5fW produces a folding behavior that is dependent on the Escherichia coli strain used to express the mutant. The orientations of the indole rings in these mutants are such that the Trp residue adopts a chi2 of approximately 90 degrees in the F104W mutant and approximately -100 degrees in the F153W mutant. Using results from 19F-1H heteronuclear NOE experiment, we show the replacement of L-Trp with 5fW at these positions does not change the orientation of the indole ring and the spread of the 5fW side-chain dihedral angles increases moderately for the F104(5fW) mutant and not at all for the F153(5fW) mutant. Based on these structures, we conclude that the substitution of Phe by 5fW at these two positions has minimal effects on the structure of cTnC and that the 5fW indole rings in both mutants have well defined orientation, making the two mutants viable candidates for use in in situ 19F NMR spectroscopy.
  Selected figure(s)  
Figure 1.
Figure 1. (A) Ribbon representation of the C-terminal domain of the wild-type chicken cTnC. Side chains of F104 and F153 (sites of mutation) are labeled red and blue, respectively. (B) Indole ring of Tryptophan. Numbering of the carbon is illustrated. Each proton is labeled using nomenclature used in the paper. In 5fW, H 3 is replaced with a ^19F atom.
Figure 6.
Figure 6. Ribbon representations of backbone superimposition of the wild-type chicken cTnC structure (PDB code 1AJ4 [PDB] ) with (A) the F104W structure (red), (B) the F104(5fW) structure (gray), (C) the F153W structure (orange), (D) the F153(5fW) structure (yellow). The wild-type structure is shown in blue in all superimpositions. RMSDs between the mutant structures and the wild-type structure are shown below each ribbon representation. In all panels, the superimposition is done using residues in structured regions only (residues 95–103, 111–123, 130–140, and 147–158).
  The above figures are reprinted by permission from the Protein Society: Protein Sci (2005, 14, 2447-2460) copyright 2005.  
  Figures were selected by an automated process.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
19052784 J.J.Panek, T.R.Ward, A.Jezierska, and M.Novic (2009).
Effects of tryptophan residue fluorination on streptavidin stability and biotin-streptavidin interactions via molecular dynamics simulations.
  J Mol Model, 15, 257-266.  
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
17915350 G.Cornilescu, E.B.Hadley, M.G.Woll, J.L.Markley, S.H.Gellman, and C.C.Cornilescu (2007).
Solution structure of a small protein containing a fluorinated side chain in the core.
  Protein Sci, 16, 2089.  
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