engleski

Influence of The Hydrophobic Residues on The Dke1 Activity

Acetylacetone dioxygenase from Acinetobacter johnsoii, Dke1, is a non-heme Fe2+ dependent enzyme that catalyzes the oxidative degradation of β-dicarbonyl compounds.1 In this work we elucidate the role of a set of hydrophobic residues lining or close to the active site, Phe59, Phe115 and Phe119, on the protein structure and activity. The variations showed a marked, 20-200 fold impact on the O2 reduction rates. Molecular dynamic studies of the substrate ligated Dke1 variants revealed an impact of the hydrophobic residues on the substrate stabilization in the active site as well as on the orientations of Glu98 and Arg80, which have previously been shown to be crucial for catalysis. 2 Compared to the wild type protein the Glu98-His104 interaction significantly reduced while the interaction between Arg80 and the N terminal from the neighbor unit increased in the PheAla mutants. The studies also revealed correlation between the number of low energy positions for O2 in the active site of Dke1 and O2 reduction rates, as well as influence of the mutations on traffic of water and ligands through the protein

diketone dioxygenaze ; Fe2+

nije evidentirano