Purification and enzymatic properties of arsenic resistance protein ArsH from heterogeneous expression in E.coli BL21
(1. School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China)
2. Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, China)
Abstract: Four arsenic-resistance genes (arsB, arsC, arsH, arsR) have been discovered in Acidithiobacillus ferrooxidans. Their gene sequences have been identified and three different arsenic-resistance mechanisms have been elucidated. However, the function of the arsH gene in At. ferrooxidans remains unclear. In order to evaluate the function of the arsH gene, we cloned it and expressed it in Escherichia coli. The protein was purified and its relative molecular mass was determined by SDS-PAGE (Sodium dodecyl sulfate-polyacrylamide gel electrophoresis). The results indicated that the relative molecular mass of the purified ArsH was approximately 29 kDa. The purified protein ArsH from E.coli BL21 was a flavoprotein that oxidized in vitro NADPH with an optimal pH of 6.4.
Key words: Acidithiobacillus ferrooxidans; protein ArsH; expression and purification; FMN reductase; NADPH