Biophysics and the Challenges of Emerging Threats

Abstract

A series of experiments that aid in the structural characterization of protein-ligand complexes by NMR have been assessed. Methods have been established to identify intermolecular NOEs between labeled proteins and unlabeled peptides and/or drug ligands, while omitting signal from intramolecular NOEs within both labeled and unlabeled constituents. The protein-peptide complex chosen to illustrate the value of such techniques is the C-terminal domain of the cardiac muscle regulatory protein Troponin C (cCTnC(91-161)) bound to the N-terminal domain of the inhibitory protein Troponin I (cTnI(35-72)). The measurement of intermolecular NOE contacts between cCTnC and cTnI(35-72) was accomplished by the (13)C-edited/filtered NOESY-HSQC [19] and (13)C-edited/filtered HMQC-NOESY [9] experiments. The assignment of the bound peptide was facilitated by the (13)C, (15)N-filtered TOCSY, and (13)C, (15)N-filtered NOESY experiments [4, 6, 15].