High-performance liquid chromatography of amino acids, peptides and proteins. CI. Identification and characterisation of coulombic interactive regions on sperm whale myoglobin by high-performance anion-exchange chromatography and computer-graphic analysis

A combination of high-performance liquid chromatographic and computer-graphic analysis of the electrostatic interactive surface of sperm whale myoglobin has allowed the putative anion-exchange binding domains to be identified and characterised. These studies have established the existence of four regions of high electrostatic potential in terms of negativity charged amino acid side chain groups. These binding sites are comprised of seven glutamic acid residues, two aspartic acid residues and two propionic acid groups located on the heme moiety which are arranged in a continuous topographic band around on section of the myoglobin surface. The number of charged groups in these interactive patches correlated with the range of experimentally determined Z_c values under different elution conditions of varying gradient time, flow-rate and displacer salt. The changes in Z_c values observed under some chromatographic conditions have been interpreted in terms of the conformational reorientation of the myoglobin molecule as it interacts with the charged stationary phase surface.