title: In silico studies of urease inhibitors to explore ligand-enzyme interactions.
abstract: In continuation of our previous study on the urease inhibition by a number of chalcones, 2,3-dihydro-1,5-benzothiazepines and 2,3,4,5-tetrahydro-1,5-benzothiazepines, FlexX docking has been exploited to get a deeper insight into the mechanism of their inhibitory action. A comparison of the IC(50) values of the active compounds reveals that, of the three classes of compounds studied, 2,3-dihydro-1,5-benzothiazepines were the most potent urease inhibitors. An in silico examination of these compounds showed that the activity is related to the interaction of ligand with the nickel metallocentre, its interaction with two amino acid residues, Asp224 and Cys322, in addition to the orientation of rings A and B in the catalytic core of the enzyme. The most active compound 2,3-dihydro-1,5-benzothiazepine (4) anchor tightly through a network of interactions with Ni701 and Ni702. This includes a number of hydrogen bonds and hydrophobic contacts with the amino acid residues in its vicinity. For their reduced analogs, the difference in the activity of different diastereomers has been observed to be configuration-dependent. This may be ascribed mainly to the difference in the orientation of ring B of the two stereoisomers and the extent of their interaction with Asp224 and Cys322 present in the catalytic core of the enzyme.
authors.affiliation: Department of Chemistry, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
authors.forename: Farzana Latif
authors.initials: FL
authors.lastname: Ansari
authors.forename: Abdul
authors.initials: A
authors.lastname: Wadood
authors.forename: Ahsan
authors.initials: A
authors.lastname: Ullah
authors.forename: Fatima
authors.initials: F
authors.lastname: Iftikhar
authors.forename: Zaheer
authors.initials: Z
authors.lastname: Ul-Haq
mesh_terms: D001581:Benzothiadiazines / Q000494:pharmacology; D001665:Binding Sites; D047188:Chalcones / Q000494:pharmacology; D003198:Computer Simulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D008024:Ligands; D015394:Molecular Structure; D013329:Structure-Activity Relationship; D014510:Urease / Q000037:antagonists & inhibitors*
chemical_list: D001581:Benzothiadiazines; D047188:Chalcones; D004791:Enzyme Inhibitors; D008024:Ligands; D014510:Urease