On the basis of three-dimensional structures of native penicillopepsine and its inhibitory complexes the model of active center has been chosen. In the model of the active site the conformational freedom of rotation has been given only to the side chains of residues Asp33, Tyr75 and Asp213. Three possible electronic state of the side chains of Asp33 and Asp213 and connected with them water molecule were considered. Using the method of theoretical conformational analysis conformational aspects of interaction of penicillopepsine with Leu-Trp and Trp-Ile dipeptides were studied. It is shown that productive noncovalent complexes of penicillopepsine with substrates are low-energy. Inside - intermolecular interactions of molecules of enzyme and substrates are aligned and do not lead to steric strain of cleavable bond. Analysis of possible orientations of hydrolyzed peptide bond and nucleophile water molecule relatively to Asp33, Tyr75 and Asp213 residues of penicillopepsine revealed the role of these residues during catalysis processes.
penicillopepsine, noncovalent complexes, conformational analysis
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