title: Homology modeling of a novel epoxide hydrolase (EH) from Aspergillus niger SQ-6: structure-activity relationship in expoxides inhibiting EH activity.
abstract: The 3D structure of a novel epoxide hydrolase from Aspergillus niger SQ-6 (sqEH) was constructed by using homology modeling and molecular dynamics simulations. Based on the 3D model, Asp191, His369 and Glu343 were predicted as catalytic triad. The putative active pocket is a hydrophobic environment and is rich in some important non-polar residues (Pro318, Trp282, Pro319, Pro317 and Phe242). Using three sets of epoxide inhibitors for docking study, the interaction energies of sqEH with each inhibitor are consistent with their inhibitory effects in previous experiments. Moreover, a critical water molecule which closes to the His369 was identified to be an ideal position for the hydrolysis step of the reaction. Two tyrosine residues (Tyr249 and Tyr312) are able to form hydrogen bonds with the epoxide oxygen atom to maintain the initial binding and positioning of the substrate in the active pocket. These docked complex models can well interpret the substrate specificity of sqEH, which could be relevant for the structural-based design of specific epoxide inhibitors.
authors.affiliation: State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, People's Republic of China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Luo
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yao
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Han
authors.forename: Yi-Han
authors.initials: YH
authors.lastname: Zhou
authors.forename: Ze-Sheng
authors.initials: ZS
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000201:enzymology*; D001665:Binding Sites; D004791:Enzyme Inhibitors / Q000737:chemistry*; D004851:Epoxide Hydrolases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D008956:Models, Chemical; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D004791:Enzyme Inhibitors; D004851:Epoxide Hydrolases