School of Minerals Processing and Bioengineering, Central South University, Changsha, Hunan, China 410083.
Biol Trace Elem Res. 2013 Apr;152(1):91-7. doi: 10.1007/s12011-012-9589-0. Epub 2013 Jan 24.
Copper resistance of acidophilic bacteria is very significant in bioleaching of copper ore since high concentration of copper are harmful to the growth of organisms. Copper resistance gene afe_1073 was putatively considered to be involved in copper homeostasis in Acidithiobacillus ferrooxidans ATCC23270. In the present study, differential expression of afe_1073 in A. ferrooxidans strain DY26 and DC was assessed with quantitative reverse transcription polymerase chain reaction. The results showed the expression of afe_1073 in two strains increased with the increment of copper concentrations. The expression of DY26 was lower than that of DC at the same copper concentration although A. ferrooxidans strain DY26 possessed higher copper resistance than strain DC. In addition, bioinformatics analysis showed AFE_1073 was a typical transmembrane protein P1b1-ATPase, which could reduce the harm of Cu(+) by pumping it out from the cell. There were two mutation sites in AFE_1073 between DY26 and DC and one may change the hydrophobicity of AFE_1073, which could enhance the ability of DY26 to pump out Cu(+). Therefore, DY26 needed less gene expression of afe_1073 for resisting copper toxicity than that of DC at the same copper stress. Our study will be beneficial to understanding the copper resistance mechanism of A. ferrooxidans.
嗜酸菌的铜抗性在铜矿的生物浸出中非常重要，因为高浓度的铜对生物的生长有害。铜抗性基因 afe_1073 被认为参与了氧化亚铁硫杆菌 ATCC23270 中的铜稳态。在本研究中，通过定量反转录聚合酶链反应评估了 afe_1073 在嗜酸菌菌株 DY26 和 DC 中的差异表达。结果表明，在两种菌株中，afe_1073 的表达随着铜浓度的增加而增加。尽管嗜酸菌菌株 DY26 的铜抗性高于菌株 DC，但在相同的铜浓度下，DY26 的表达低于 DC。此外，生物信息学分析表明 AFE_1073 是一种典型的跨膜蛋白 P1b1-ATPase，可通过将其从细胞中泵出，减少 Cu(+) 的危害。在 DY26 和 DC 之间，AFE_1073 有两个突变位点，其中一个可能改变 AFE_1073 的疏水性，从而增强 DY26 泵出 Cu(+)的能力。因此，在相同的铜胁迫下，DY26 抵抗铜毒性所需的 afe_1073 基因表达量低于 DC。我们的研究将有助于理解氧化亚铁硫杆菌的铜抗性机制。
