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Characterization of Thiomonas delicata arsenite oxidase expressed in Escherichia coli

Teoh, W. K. and Salleh, F. M. and Shahir, S. (2017) Characterization of Thiomonas delicata arsenite oxidase expressed in Escherichia coli. 3 Biotech, 7 (2). ISSN 2190-572X

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Abstract

Microbial arsenite oxidation is an essential biogeochemical process whereby more toxic arsenite is oxidized to the less toxic arsenate. Thiomonas strains represent an important arsenite oxidizer found ubiquitous in acid mine drainage. In the present study, the arsenite oxidase gene (aioBA) was cloned from Thiomonas delicata DSM 16361, expressed heterologously in E. coli and purified to homogeneity. The purified recombinant Aio consisted of two subunits with the respective molecular weights of 91 and 21 kDa according to SDS-PAGE. Aio catalysis was optimum at pH 5.5 and 50–55 °C. Aio exhibited stability under acidic conditions (pH 2.5–6). The Vmax and Km values of the enzyme were found to be 4 µmol min−1 mg−1 and 14.2 µM, respectively. SDS and Triton X-100 were found to inhibit the enzyme activity. The homology model of Aio showed correlation with the acidophilic adaptation of the enzyme. This is the first characterization studies of Aio from a species belonging to the Thiomonas genus. The arsenite oxidase was found to be among the acid-tolerant Aio reported to date and has the potential to be used for biosensor and bioremediation applications in acidic environments.

Item Type:Article
Uncontrolled Keywords:Acidic tolerance, Arsenite oxidase, Molecular modeling, Recombinant expression, Thiomonas delicata
Subjects:Q Science > QH Natural history > QH301 Biology
Divisions:Biosciences and Medical Engineering
ID Code:75133
Deposited By: Fazli Masari
Deposited On:27 Mar 2018 13:53
Last Modified:27 Mar 2018 13:53

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