biostudies-literatureUnknown16(6)Jensen CNBiotechnology and Biological Sciences Research CouncilThe FAD-dependent monooxygenase HbpA from Pseudomonas azelaica HBP1 catalyses the hydroxylation of 2-hydroxybiphenyl (2HBP) to 2,3-dihydroxybiphenyl (23DHBP). HbpA has been used extensively as a model for studying flavoprotein hydroxylases under process conditions, and has also been subjected to directed-evolution experiments that altered its catalytic properties. The structure of HbpA has been determined in its apo and FAD-complex forms to resolutions of 2.76 and 2.03 Å, respectively. Comparisons of the HbpA structure with those of homologues, in conjunction with a model of the reaction product in the active site, reveal His48 as the most likely acid/base residue to be involved in the hydroxylation mechanism. Mutation of His48 to Ala resulted in an inactive enzyme. The structures of HbpA Chembiochem : a European journal of chemical biology968-76https://www.ebi.ac.uk/biostudies/studies/S-EPMC4515095biostudies-literatureStructures of the Apo and FAD-bound forms of 2-hydroxybiphenyl 3-monooxygenase (HbpA) locate activity hotspots identified by using directed evolution.PMC4515095Turkenburg JPFrank AMielke THart SMan HJensen CNFarrugia JEGrogan GfalseStructures of the Apo and FAD-bound forms of 2-hydroxybiphenyl 3-monooxygenase (HbpA) locate activity hotspots identified by using directed evolution.The FAD-dependent monooxygenase HbpA from Pseudomonas azelaica HBP1 catalyses the hydroxylation of 2-hydroxybiphenyl (2HBP) to 2,3-dihydroxybiphenyl (23DHBP). HbpA has been used extensively as a model for studying flavoprotein hydroxylases under process conditions, and has also been subjected to directed-evolution experiments that altered its catalytic properties. The structure of HbpA has been determined in its apo and FAD-complex forms to resolutions of 2.76 and 2.03 Å, respectively. Comparisons of the HbpA structure with those of homologues, in conjunction with a model of the reaction product in the active site, reveal His48 as the most likely acid/base residue to be involved in the hydroxylation mechanism. Mutation of His48 to Ala resulted in an inactive enzyme. The structures of HbpA 2015-01-01T00:00:00Z2015 Apr2025-04-04T09:12:39.47Z2019-03-27T01:55:48ZS-EPMC45150952573730610.1002/cbic.201402701