title: Role of tyrosine 131 in the active site of paAzoR1, an azoreductase with specificity for the inflammatory bowel disease prodrug balsalazide.
abstract: Azoreductase 1 from Pseudomonas aeruginosa strain PAO1 (paAzoR1) catalyses the activation of the prodrug balsalazide and reduces the azo dye methyl red using reduced nicotinamide adenine dinucleotide cofactor as an electron donor. To investigate the mechanism of the enzyme, a Y131F mutation was introduced and the enzymic properties of the mutant were compared with those of the wild-type enzyme. The crystallographic structure of the mutant with methyl red bound was solved at 2.1 A resolution and compared with the wild-type structure. Tyr131 is important in the architecture of the active site but is not essential for enzymic activity.
authors.affiliation: Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, England.
authors.forename: Chan-Ju
authors.initials: CJ
authors.lastname: Wang
authors.forename: Nicola
authors.initials: N
authors.lastname: Laurieri
authors.forename: Areej
authors.initials: A
authors.lastname: Abuhammad
authors.forename: Edward
authors.initials: E
authors.lastname: Lowe
authors.forename: Isaac
authors.initials: I
authors.lastname: Westwood
authors.forename: Ali
authors.initials: A
authors.lastname: Ryan
authors.forename: Edith
authors.initials: E
authors.lastname: Sim
mesh_terms: D001391:Azo Compounds; D002384:Catalysis; D020134:Catalytic Domain / Q000235:genetics; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D006358:Hot Temperature; D007700:Kinetics; D019804:Mesalamine / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009243:NAD / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D009601:Nitroreductases; D010659:Phenylhydrazines / Q000378:metabolism; D017510:Protein Folding; D011550:Pseudomonas aeruginosa / Q000201:enzymology; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D010659:Phenylhydrazines; D009243:NAD; D014443:Tyrosine; D019804:Mesalamine; C008492:methyl red; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase; C038637:balsalazide