A STRUCTURAL STUDY OF PEPTIDES AND PROTEINS CONTAINING L-ALANINE RESIDUES BY C-13 NMR-SPECTROSCOPY COMBINED WITH AB-INITIO CHEMICAL-SHIFT CALCULATIONS

From the observation of solid-state C-13 NMR chemical shifts of L-alanine residues which are contained in some peptides, and the C-13 chemical shift calculations employing the coupled-Hartree Fock method with gauge-invariant-atomic-orbital, it was found that the C-13 chemical shift of the C(beta)-carbon in the L-alanine residue is related to the main-chain dihedral angles, phi, psi, but that of the C(alpha)-carbon is affected not only by dihedral angles but also by hydrogen-bonding structure. These results were successfully applied to the structural study of proteins in solution, ribonuclease H from Escherichia coli and basic pancreatic trypsin inhibitor.