恶臭假单胞菌S4菌株对镍离子的摄取：镁离子摄取泵的潜在作用

Ni2+-uptake in Pseudomonas putida strain S4: a possible role of Mg2+-uptake pump.

作者信息

Tripathi V N, Srivastava S

机构信息

Department of Genetics, University of Delhi, South Campus, New Delhi, India.

出版信息

J Biosci. 2006 Mar;31(1):61-7. doi: 10.1007/BF02705236.

DOI:10.1007/BF02705236

PMID:16595876

Abstract

Essential metal ion homeostasis is based on regulated uptake of metal ions, both during its scarcity and abundance. Pseudomonas putida strain S4, a multimetal resistant bacterium, was employed to investigate Ni(2+) entry into cells. It was observed that Mg(2+) regulates the entry of Ni(2+) and by this plays a protective role to minimize Ni(2+) toxicity in this strain. This protection was evident in both growth as well as viability. Intracellular accumulation of Ni(2+) varied in accordance with Mg(2+) concentrations in the medium. It was hypothesized that Ni(2+) enters the cell using a broad Mg(2+) pump, i.e. the CorA system, as the CorA inhibitor, i.e. Co(III) Hex, also inhibits Ni 2+ uptake. This led to the inference that Mg(2+)-based protection was basically due to competitive inhibition of Ni(2+) uptake. We also show that Zn(2+) can further regulate the entry of Ni(2+).

摘要

必需金属离子稳态基于在金属离子稀缺和丰富时对其摄取的调节。恶臭假单胞菌菌株S4是一种多金属抗性细菌，用于研究镍离子（Ni(2+)）进入细胞的过程。据观察，镁离子（Mg(2+)）调节Ni(2+)的进入，并由此在该菌株中发挥保护作用，将Ni(2+)毒性降至最低。这种保护在生长和活力方面都很明显。Ni(2+)的细胞内积累随培养基中Mg(2+)浓度的变化而变化。据推测，Ni(2+)通过一个广泛的Mg(2+)泵即CorA系统进入细胞，因为CorA抑制剂即三价钴六胺络合物（Co(III) Hex）也抑制Ni(2+)的摄取。由此推断，基于Mg(2+)的保护主要是由于对Ni(2+)摄取的竞争性抑制。我们还表明，锌离子（Zn(2+)）可以进一步调节Ni(2+)的进入。