X-ray structure of a human cardiac muscle troponin C/troponin I chimera in two crystal forms.
Yan, C., Sack, J.S.(2022) Acta Crystallogr F Struct Biol Commun 78: 17-24
- PubMed: 34981771 
- DOI: https://doi.org/10.1107/S2053230X21012395
- Primary Citation of Related Structures:  
7SC2, 7SC3 - PubMed Abstract: 
The X-ray crystal structure of a human cardiac muscle troponin C/troponin I chimera has been determined in two different crystal forms and shows a conformation of the complex that differs from that previously observed by NMR. The chimera consists of the N-terminal domain of troponin C (cTnC; residues 1-80) fused to the switch region of troponin I (cTnI; residues 138-162). In both crystal forms, the cTnI residues form a six-turn α-helix that lays across the hydrophobic groove of an adjacent cTnC molecule in the crystal structure. In contrast to previous models, the cTnI helix runs in a parallel direction relative to the cTnC groove and completely blocks the calcium desensitizer binding site of the cTnC-cTnI interface.
Organizational Affiliation: 
Small Molecule Drug Discovery, Bristol Myers Squibb Research and Development, PO Box 4000, Princeton, NJ 08543-4000, USA.