Novel Gene Encoding 5-Aminosalicylate 1,2-Dioxygenase from Comamonas sp. Strain QT12 and Catalytic Properties of the Purified Enzyme.

ABSTRACT: The 1,125-bp mabB gene encoding 5-aminosalicylate (5ASA) 1,2-dioxygenase, a nonheme iron dioxygenase in the bicupin family that catalyzes the cleavage of the 5ASA aromatic ring to form cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate in the biodegradation of 3-aminobenzoate, was cloned from Comamonas sp. strain QT12 and characterized. The deduced amino acid sequence of the enzyme has low sequence identity with that of other reported ring-cleaving dioxygenases. MabB was heterologously expressed in Escherichia coli cells and purified as a His-tagged enzyme. The optimum pH and temperature for MabB are 8.0 and 10°C, respectively. FeII is required for the catalytic activity of the purified enzyme. The apparent Km and Vmax values of MabB for 5ASA are 52.0 ± 5.6 μM and 850 ± 33.2 U/mg, respectively.

SUBMITTER: Yu H 

PROVIDER: S-EPMC5717158 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature