Systematic application of two-dimensional h-1-NMR techniques for studies of proteins .1. Combined use of spin-echo-correlated spectroscopy and j-resolved spectroscopy for the identification of complete spin systems of non-labile protons in amino-acid-residues
This and the following paper describe the practical application of recently developed, two-dimensional nuclear magnetic resonance techniques for studies of proteins. In the present report spin-echo-correlated spectroscopy and two-dimensional J-resolved spectroscopy are used to identify complete spin systems of non-labile, aliphatic protons in the basic pancreatic trypsin inhibitor. Overall, 41 out of the 58 aliphatic spin systems in this protein were identified; for the first time the spin systems of all the glycyl residues in a protein have been identified in the 1H NMR spectrum. Combined with the following paper, the present data yield new individual assignments for numerous amino acid residues and provide a new avenue, based on accurate measurements of spin-spin coupling constants in the two-dimensional J-resolved spectra, for studying changes of static and dynamic aspects of protein conformation between single crystals and solution, or between different conditions of solvent and temperature.