1fi5

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spinqualitylabelsall models PDB ID 1fi5 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
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Resources:	FirstGlance, OCA, PDBsum, RCSB
Coordinates:	save as pdb, mmCIF, xml

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

Overview

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.

About this Structure

1FI5 is a Single protein structure of sequence from Gallus gallus. This structure supersedes the now removed PDB entry 1GGS. Full crystallographic information is available from OCA.

Reference

Solution structures of the C-terminal domain of cardiac troponin C free and bound to the N-terminal domain of cardiac troponin I., Gasmi-Seabrook GM, Howarth JW, Finley N, Abusamhadneh E, Gaponenko V, Brito RM, Solaro RJ, Rosevear PR, Biochemistry. 1999 Jun 29;38(26):8313-22. PMID:10387077

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