Copper ions stimulate polyphosphate degradation and phosphate efflux in Acidithiobacillus ferrooxidans
Copper ions stimulate polyphosphate degradation and phosphate efflux in Acidithiobacillus ferrooxidans
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DOI：
10.1128/aem.70.9.5177-5182.2004
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发表时间：
2004-09-01
影响因子：
4.4
通讯作者：
Jerez, CA
中科院分区：
文献类型：
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作者：
Alvarez, S;Jerez, CA
对于一些细菌和藻类，已经提出无机多磷酸盐和金属-磷酸盐络合物的运输可能参与重金属耐受性。为了在氧化亚铁硫杆菌（一种对重金属具有高水平抗性的微生物）中测试这种可能性，当细菌在高铜浓度（100 mM）中生长或转移到高铜浓度（100 mM）时，测定多磷酸盐水平。在这些条件下，细胞表现出快速下降的多磷酸盐水平，伴随着外聚磷酸酶活性的增加和磷酸盐流出的刺激。铜在1至2 μ M范围内极大地刺激了A.氧化亚铁镉和锌的情况也是如此，但程度较轻。生物信息学分析表明，A. ferrooxidans ATCC 23270基因组序列没有显示出磷酸盐流出的推定pit基因，而是显示出在一级和二级结构上与在酸性pH（Pho 84）下起作用的酿酒酵母磷酸盐转运蛋白相似的开放阅读框架。我们的研究结果支持了一个模型，金属解毒，重金属刺激多磷酸盐水解和金属磷酸盐络合物形成的运输出细胞的一部分，可能是功能性的重金属耐受机制在A。氧化亚铁
For some bacteria and algae, it has been proposed that inorganic polyphosphates and transport of metal-phosphate complexes could participate in heavy metal tolerance. To test for this possibility in Acidithiobacillus ferrooxidans, a microorganism with a high level of resistance to heavy metals, the polyphosphate levels were determined when the bacterium was grown in or shifted to the presence of a high copper concentration (100 mM). Under these conditions, cells showed a rapid decrease in polyphosphate levels with a concomitant increase in exopolyphosphatase activity and a stimulation of phosphate efflux. Copper in the range of 1 to 2 muM greatly stimulated exopolyphosphatase activity in cell extracts from A. ferrooxidans. The same was seen to a lesser extent with cadmium and zinc. Bioinformatic analysis of the available A. ferrooxidans ATCC 23270 genomic sequence did not show a putative pit gene for phosphate efflux but rather an open reading frame similar in primary and secondary structure to that of the Saccharomyces cerevisiae phosphate transporter that is functional at acidic pH (Pho84). Our results support a model for metal detoxification in which heavy metals stimulate polyphosphate hydrolysis and the metal-phosphate complexes formed are transported out of the cell as part of a possibly functional heavy metal tolerance mechanism in A. ferrooxidans.