1NPQ

structure of a rhodamine-labeled N-domain Troponin C mutant (Ca2+ saturated) in complex with skeletal Troponin I 115-131


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 21 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

NMR Structure of a Bifunctional Rhodamine Labeled N-Domain of Troponin C Complexed with the Regulatory "Switch" Peptide from Troponin I: Implications for in Situ Fluorescence Studies in Muscle Fibers

Mercier, P.Ferguson, R.E.Irving, M.Corrie, J.E.T.Trentham, D.R.Sykes, B.D.

(2003) Biochemistry 42: 4333-4348

  • DOI: 10.1021/bi027041n

  • PubMed Abstract: 
  • The structure of the calcium-saturated regulatory domain of skeletal troponin C (sNTnC) complexed with the switch peptide comprising residues 115-131 of troponin I (TnI), and with a bifunctional rhodamine fluorescent label attached to residues 56 (E5 ...

    The structure of the calcium-saturated regulatory domain of skeletal troponin C (sNTnC) complexed with the switch peptide comprising residues 115-131 of troponin I (TnI), and with a bifunctional rhodamine fluorescent label attached to residues 56 (E56C) and 63 (E63C) on the C helix of sNTnC, has been determined using nuclear magnetic resonance (NMR) spectroscopy. The structure shows that the integrity of the C helix is not altered by the E(56,63)C mutations or by the presence of the bifunctional rhodamine and that the label does not interact with the hydrophobic cleft of sNTnC. Moreover, the overall fold of the protein and the position of the TnI peptide are similar to those observed previously with related cardiac NTnC complexes with residues 147-163 of cardiac TnI [Li et al. (1999) Biochemistry 38, 8289-8298] and including the drug bepridil [Wang et al. (2002) J. Biol. Chem. 277, 31124-31133]. The degree of opening of the structure is reduced as compared to that of calcium-saturated sNTnC in the absence of the switch peptide [Gagné et al. (1995) Nat. Struct. Biol. 2, 784-789]. The switch peptide is bound in a shallow and complementary hydrophobic surface cleft largely defined by helices A and B and also has key ionic interactions with sNTnC. These results show that bifunctional rhodamine probes can be attached to surface helices via suitable pairs of solvent-accessible residues that have been mutated to cysteines, without altering the conformation of the labeled domain. A set of such probes can be used to determine the orientation and motion of the target domain in the cellular environment [Corrie et al. (1999) Nature 400, 425-430; Ferguson et al. (2003) Mol. Cell 11(4), in press].


    Organizational Affiliation

    CIHR Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Troponin C
A
90Gallus gallusMutation(s): 2 
Gene Names: TNNC2
Find proteins for P02588 (Gallus gallus)
Go to Gene View: TNNC2
Go to UniProtKB:  P02588
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Troponin I
B
17Oryctolagus cuniculusMutation(s): 0 
Gene Names: TNNI2
Find proteins for P02643 (Oryctolagus cuniculus)
Go to Gene View: TNNI2
Go to UniProtKB:  P02643
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 21 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 1NPQ Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-04-29
    Type: Initial release
  • Version 1.1: 2007-10-21
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance