NMR studies of the interactions of substrates with enzymes and their peptide fragments

Abstract

Metal-nucleus distances measured by paramagnetic effects on T1 and interproton distances measured by the nuclear Overhauser effect have been used to determine the conformations, arrangement, locations of enzyme-bound substrates with respect to specific amino acid residues, and to dock them into X-ray structures of enzymes. Synthetic peptide fragments of enzymes that range from 45 to 50 residues in length in some cases retain enough secondary and tertiary structure to bind substrates with affinities and in conformations similar to those found on the complete enzymes. The entire structure of peptides of this size can be determined in solution by 2-dimensional nuclear magnetic resonance (NMR) methods. The applications of NMR methods to enzymology are exemplified by studies of adenylate kinase, ketosteroid isomerase, staphylococcal nuclease, and DNA polymerase I.--Mildvan, A. S. NMR studies of the interactions of substrates with enzymes and their peptide fragments.