| Title |
The ATPase Activity of The G2alt Gene Encoding an Aluminium Tolerance Protein from Anoxybacillus gonensis G2 |
| Author |
Fatih Saban Beris1,2, Lina De Smet2, Hakan Karaoglu3, Sabriye Canakci3, Jozef Van Beeumen2, and Ali Osman Belduz3* |
| Address |
1Department of Biology, Faculty of Arts & Sciences, Rize University, 53100, Rize, Turkey, 2Laboratory for Protein Biochemistry and Protein Engineering, Faculty of Sciences, Ghent University, 9000 Gent, Belgium, 3Department of Biology, Faculty of Arts&Sciences, Karadeniz Technical University, 61080, Trabzon, Turkey |
| Bibliography |
Journal of Microbiology, 49(4),641-650, 2011,
|
| DOI |
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| Key Words |
aluminium tolerance gene (G2alt), aluminium tolerance protein (G2ALT), ATPase, cloning, aluminium tolerance, Anoxybacillus gonensis G2 |
| Abstract |
The G2ALT gene was cloned and sequenced from the thermophilic bacterium Anoxybacillus gonensis G2.
The gene is 666 bp long and encodes a protein 221 amino acids in length. The gene was overexpressed
in E. coli and purified to homogeneity and biochemically characterized. The enzyme has a molecular mass
of 24.5 kDa and it could be classified as a member of the family of bacterial aluminium resistance proteins
based on homology searches. When this fragment was expressed in E. coli, it endowed E. coli with Al
tolerance to 500 μM. The purified G2ALT protein is active at a broad pH range (pH 4.0-10.0) and temperature
range (25°C-80°C) with optima of 6.0 and the apparent optimal temperature of 73°C respectively.
Under optimal conditions, G2ALT exhibited a low ATPase activity with Km- and Vmax- values of 10±0.55
μM and 26.81±0.13 mg Pi released/min/mg enzyme, respectively. The ATPase activity of G2ALT requires
Mg2+ and Na+ ions, while Zn2+ and Al3+ stimulate the activity. Cd2+ and Ag+ reduced the activity and Li+,
Cu2+, and Co2+ inhibited the activity. Known inhibitors of most ATPases, like such as β-mercaptoethanol
and ouabain, also inhibited the activity of the G2ALT. These biochemical characterizations suggested that
G2ALT belongs to the PP-loop ATPase superfamily and it can be responsible for aluminium tolerance
in A. gonensis G2. |
