How Metal Coordination in the Ca-, Ce-, and Eu-Containing Methanol Dehydrogenase Enzymes Can Influence the Catalysis: A Theoretical Point of View

Abstract

Methanol dehydrogenase (MDH) enzymes are quinoproteins that require calcium or magnesium ion as well as pyrroloquinoline quinone as a cofactor for activity in the oxidation of methanol to formaldehyde. Lately, MDH enzymes containing lanthanide ions in the active site have been isolated in drastic conditions from Methylacidiphilum fumariolicum bacterium. The present theoretical study performed in the framework of the density functional theory employing the quantum mechanical cluster approach mainly focused on the catalytic mechanism of cerium containing MDH enzyme. In order to rationalize the effect of the metal ion substitution on the catalytic activity, geometrical and electronic properties of the “Michaelis–Menten” enzyme–methanol complexes of Ce-MDH and Eu-MDH are also discussed as well as the substrate’s activation mediated by the metal ion. With the aim to better describe the Lewis acidity of metal ions in the methanol oxidation, the comparison of the catalytic performance between Ce-MDH and Ca-MDH was also made.