1FI5

NMR STRUCTURE OF THE C TERMINAL DOMAIN OF CARDIAC TROPONIN C BOUND TO THE N TERMINAL DOMAIN OF CARDIAC TROPONIN I.

Replaces:  1GGS

Summary for 1FI5

• Entry DOI: 10.2210/pdb1fi5/pdb
• Descriptor: PROTEIN (TROPONIN C), CALCIUM ION (2 entities in total)
• Functional Keywords: troponin c-troponin i interaction, cardiac, muscle protein, calcium binding protein, contractile protein
• Biological source: Gallus gallus (chicken)
• Total number of polymer chains: 1
• Total formula weight: 9543.69

Authors

Gasmi-Seabrook, G.M.,Howarth, J.W.,Finley, N.,Abusamhadneh, E.,Gaponenko, V.,Brito, R.M.,Solaro, R.J.,Rosevear, P.R. (deposition date: 2000-08-03, release date: 2000-08-23, Last modification date: 2024-05-22)

Primary citation

Gasmi-Seabrook, G.M.,Howarth, J.W.,Finley, N.,Abusamhadneh, E.,Gaponenko, V.,Brito, R.M.,Solaro, R.J.,Rosevear, P.R.
Solution structures of the C-terminal domain of cardiac troponin C free and bound to the N-terminal domain of cardiac troponin I.
Biochemistry, 38:8313-8322, 1999

PubMed Abstract: The N-terminal domain of cardiac troponin I (cTnI) comprising residues 33-80 and lacking the cardiac-specific amino terminus forms a stable binary complex with the C-terminal domain of cardiac troponin C (cTnC) comprising residues 81-161. We have utilized heteronuclear multidimensional NMR to assign the backbone and side-chain resonances of Ca2+-saturated cTnC(81-161) both free and bound to cTnI(33-80). No significant differences were observed between secondary structural elements determined for free and cTnI(33-80)-bound cTnC(81-161). We have determined solution structures of Ca2+-saturated cTnC(81-161) free and bound to cTnI(33-80). While the tertiary structure of cTnC(81-161) is qualitatively similar to that observed free in solution, the binding of cTnI(33-80) results mainly in an opening of the structure and movement of the loop region between helices F and G. Together, these movements provide the binding site for the N-terminal domain of cTnI. The putative binding site for cTnI(33-80) was determined by mapping amide proton and nitrogen chemical shift changes, induced by the binding of cTnI(33-80), onto the C-terminal cTnC structure. The binding interface for cTnI(33-80), as suggested from chemical shift changes, involves predominantly hydrophobic interactions located in the expanded hydrophobic pocket. The largest chemical shift changes were observed in the loop region connecting helices F and G. Inspection of available TnC sequences reveals that these residues are highly conserved, suggesting a common binding motif for the Ca2+/Mg2+-dependent interaction site in the TnC/TnI complex.

PubMed: 10387077
DOI: 10.1021/bi9902642

Experimental method

SOLUTION NMR