Macromolecule Content

• Total Structure Weight: 10419.12 
• Atom Count: 721 
• Residue Count: 89 
• Unique protein chains: 1

2KFX

Structure of the N-terminal domain of human cardiac troponin C bound to calcium ion and to the inhibitor W7

• DOI: 10.2210/pdb2KFX/pdb
• BMRB: 16190

• Classification: METAL BINDING PROTEIN
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): 2 


• Deposited: 2009-02-28 Released: 2009-06-09 
• Deposition Author(s): Hoffman, R.M.B., Sykes, B.D.

---

Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 50 
• Conformers Submitted: 10 
• Selection Criteria: structures with the lowest energy 

Literature

Structure of the inhibitor W7 bound to the regulatory domain of cardiac troponin C.

Hoffman, R.M., Sykes, B.D.

(2009) Biochemistry 48: 5541-5552

• PubMed: 19419198 
• DOI: 10.1021/bi9001826


• PubMed Abstract: 
  

The calmodulin antagonist W7 binds to troponin C in the presence of Ca(2+) and inhibits striated muscle contraction. This study integrates multiple data into the structure of the regulatory domain of human cardiac troponin C (cNTnC) bound to Ca(2+) and W7. The protein-W7 interface is defined through a three-dimensional {(1)H,(13)C}-edited-{(1)H,(12)C}-detected NOESY NMR experiment, and other aspects of the structure are modeled as perturbations to previously known coordinates and restraints. The structure determination protocol optimizes the protein-W7 contacts prior to the introduction of protein-W7 steric interactions or conformational changes in the protein. The structure determination protocol gives families of conformers that all have an optimal docking as assessed by satisfaction of the target function. The structure supports the previously proposed troponin I blocking mechanism for the activity of W7 in striated muscle and suggests a role for the flexible tail of W7 in stabilization of the bound state. This clarifies the structure-activity relationships of W7 and implicates an electrostatically mediated component of activity in common analogues of W7, including the antipsychotic trifluoroperazine and the cardiotonic levosimendan.

---

Related Citations: 

• Structure of the regulatory N-domain of human cardiac troponin C in complex with human cardiac troponin I147-163 and bepridil.
  Wang, X.,Li, M.X.,Sykes, B.D.
  (2002) J.Biol.Chem. 277: 31124
• Binding of cardiac troponin-I147-163 induces a structural opening in human cardiac troponin-C.
  Li, M.X.,Spyracopoulos, L.,Sykes, B.D.
  (1999) Biochemistry 38: 8289




---

Organizational Affiliation: 

Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Troponin C, slow skeletal and cardiac muscles	T	89	Homo sapiens	Mutation(s): 2  Gene Names: TNNC1 (TNNC)
Find proteins for P63316 (Homo sapiens) Go to Gene View: TNNC1 Go to UniProtKB:  P63316

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
WW7	T	N-(6-AMINOHEXYL)-5-CHLORO-1-NAPHTHALENESULFONAMIDE C16 H21 Cl N2 O2 S IDEHCMNLNCJQST-UHFFFAOYSA-N
CA	T	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

External Ligand Annotations
ID	Binding Affinity (Sequence Identity %)
WW7	Kd: 100000 nM PDBBIND

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 50 
• Conformers Submitted: 10 
• Selection Criteria: structures with the lowest energy 
• Olderado: 2KFX Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2009-02-28 
• Released Date: 2009-06-09 
• Deposition Author(s): Hoffman, R.M.B., Sykes, B.D.

Revision History 

• Version 1.0: 2009-06-09
  Type: Initial release
• Version 1.1: 2011-07-13
  Type: Version format compliance