Desulfovibrio DA2_CueO is a novel multicopper oxidase with cuprous, ferrous and phenol oxidase activity

• Published in: Microbiology
• Main Authors: Mancini, Stefano, Kumar, Ranjeet, Mishra, Veena, Solioz, Marc
• Format: Article in Journal/Newspaper
• Language: English
• Published: Society for General Microbiology 2017
• Subjects: 610 Medicine & health; Norilsk; norilsk
• Online Access: https://boris.unibe.ch/109645/

Desulfovibrio sp. A2 is a novel Gram-negative sulfate-reducing bacterium that was isolated from sediments of the Norilsk mining/smelting area in Russia. The organism possesses a monocistronic operon encoding a 71 kDa periplasmic multicopperoxidase, which we call DA2_CueO. Histidine-tagged DA2_CueO expressed from a plasmid in Escherichia coli and purified by Ni–NTA affinity chromatography oxidizes Cu+ and Fe2+, and exhibits phenol oxidase activity with 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), 2,3-dihydroxybenzoic acid and 2,6-dimethoxyphenol as substrates, using O2 as the oxidant. When expressed in an E. coli cueO knock-out strain, DA2_CueO exhibits phenol oxidase activity in vivo and enhances the copper tolerance of the strain. These findings indicate that the DA2_CueO gene of Desulfovibrio sp. A2 encodes a multicopperoxidase with a role in metal ion resistance. The enzyme displays some novel structural features, which are discussed.