Abstract
Ribonuclease A is well known from X-ray diffraction analysis as an enzyme which changes the conformation, when the substrate binds with the enzyme. Therefore amino acids were rotated in order to simulate the coupling movements of the amino acid side chains, water molecule, and the substrate. From the study of the movements of amino acids and the quantum chemioal calculations, a charge relay structure composed of Asp121, His 119 and a water molecule was simulated in the active site of the ribonuclease A. And the water located in the very position where the hydroxyl group of the water molecule can attack phosphorus of the substrate in the second step of the hydrolysis. Moreover it was reported that Lys 7 as well as Lys 41 may participate in the enzymatic reaction.
