Calcium-induced peptide association to form an intact protein domain: 1H NMR structur
 

Calcium-induced peptide association to form an intact protein domain: 1H NMR structural evidence.

Related Articles Calcium-induced peptide association to form an intact protein domain: 1H NMR structural evidence.

Science. 1990 Jul 20;249(4966):280-3

Authors: Shaw GS, Hodges RS, Sykes BD

The 70-residue carboxyl-terminal domain of the muscle contractile protein troponin-C contains two helix-loop-helix calcium (Ca)-binding sites that are related to each other by approximate twofold rotational symmetry. Hydrophobic residues from the helices and a short three residue beta sheet at the interface of the two sites act to stabilize the protein domain in the presence of Ca. A synthetic 34-residue peptide representing one of these sites (site III) has been synthesized and studied by H-1 nuclear magnetic resonance (NMR) spectroscopy. In solution this peptide undergoes a Ca-induced conformational change to form the helix-loop-helix Ca-binding motif. Two-dimensional nuclear Overhauser effect spectra have provided evidence for the formation of a beta sheet and interactions between several hydrophobic residues from opposing helices as found in troponin-C. It is proposed that a symmetric two-site dimer similar in tertiary structure to the carboxyl-terminal domain of troponin-C forms from the assembly of two site III peptides in the Ca-bound form.

PMID: 2374927 [PubMed - indexed for MEDLINE]



Source: PubMed