title: Molecular structure of D-hydantoinase from Bacillus sp. AR9: evidence for mercury inhibition.
abstract: Stereospecific conversion of hydantoins into their carbamoyl acid derivatives could be achieved by using the enzyme hydantoinase. Specific hydantoinases convert either the D-form or the L-form of the hydantoin and the amino acids responsible for stereospecificity have not been identified. Structural studies on hydantoinases from a few bacterial species were published recently. The structure of a thermostable D-hydantoinase from Bacillus sp. AR9 (bar9HYD) was solved to 2.3 angstroms resolution. The usual modification of carboxylation of the active-site residue Lys150 did not happen in bar9HYD. Two manganese ions were modelled in the active site. Through biochemical studies, it was shown that mercury inhibits the activity of the enzyme. The mercury derivative provided some information about the binding site of the mercuric inhibitors and a possible reason for inhibition is presented.
authors.affiliation: Institute of Microbial Technology, Sector 39-A, Chandigarh 160 036, India. kishan@imtech.res.in
authors.forename: K V
authors.initials: KV
authors.lastname: Radha Kishan
authors.forename: Rakesh M
authors.initials: RM
authors.lastname: Vohra
authors.forename: K
authors.initials: K
authors.lastname: Ganesan
authors.forename: Vishal
authors.initials: V
authors.lastname: Agrawal
authors.forename: Vishva Mitra
authors.initials: VM
authors.lastname: Sharma
authors.forename: Rakesh
authors.initials: R
authors.lastname: Sharma
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006827:Hydantoins / Q000378:metabolism; D008345:Manganese / Q000737:chemistry; D008628:Mercury / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D006827:Hydantoins; D008345:Manganese; D000581:Amidohydrolases; C020047:dihydropyrimidinase; D008628:Mercury