Homology modeling and molecular dynamics simulation studies of human type 1 3β-hydroxysteroid dehydrogenase: Toward...

The human type 1 isoform of 3β-hydroxysteroid dehydrogenase is a member of short-chain oxidoreductase family that catalyzes the conversion of dehydroepiandrosterone to androstenedione. To compare the molecular events underlying cofactor specificity in the wild-type and D35A/K36R mutant enzymes, molecular dynamics (MD) simulations of fully solvated cofactor-3β-HSD1 (wild-type and mutant) complex are performed. Molecular modeling methods are applied to construct three-dimensional models of cofactor-3β-HSD1 complexes based on Uridine diphosphate (UDP)-galactose 4-epimerase crystal structure from Escherichia coli. The binding mode and binding energy analysis between four different complexes indicate that Asp35 and Lys36 are key residues for the cofactor specificity of 3β-HSD1, which is in agreement with mutagenesis studies results obtained by Thomas et al.8 The MD results also display that the residue Glu41 may be another important residue except Asp35 and Lys36 for the cofactor specificity and that this result needs further mutational experiment for validation.