Iron-uptake in the Euryarchaeon Halobacterium salinarum
Iron-uptake in the Euryarchaeon Halobacterium salinarum
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DOI：
10.1007/s10534-006-9064-5
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发表时间：
2007-06-01
期刊：
影响因子：
3.5
通讯作者：
Anemueller, Stefan
中科院分区：
文献类型：
--
作者：
Hubmacher, Dirk;Matzanke, Berthold F.;Anemueller, Stefan
在大量原核生物和真核生物中对铁的吸收进行了深入研究，但古细菌除外，古细菌主要在极端环境中生长。本研究分析了极嗜盐广古菌盐杆菌 JW 5 菌株的铁转运机制。在低铁生长条件下，培养物上清液中未检测到铁载体。然而，各种异铁载体支持盐杆菌的生长。在 [Fe-55]-[C-14] 双标记实验中，H. salinarum 表现出对铁的吸收，但不吸收螯合剂柠檬酸盐。铁的吸收被氰化物抑制，在较高浓度下被Ga抑制。此外，测定了细胞中铁吸收的K-M为2.36μM，V-max为约67pmol Fe/min/mg蛋白质。在 Ga 不存在和存在的情况下测量了 [Fe-55] 吸收动力学。仅在非常高的 Ga 浓度下铁的吸收才会受到抑制。结果表明，H. salinarum 的铁吸收过程依赖于能量，并表明金属在膜水平上被还原。
Iron-uptake is well studied in a plethora of pro- and eukaryotic organisms with the exception of Archaea, which thrive mainly in extreme environments. In this study, the mechanism of iron transport in the extremely halophilic Euryarchaeon Halobacterium salinarum strain JW 5 was analyzed. Under low-iron growth conditions no siderophores were detectable in culture supernatants. However, various xenosiderophores support growth of H. salinarum. In [Fe-55]-[C-14] double-label experiments, H. salinarum displays uptake of iron but not of the chelator citrate. Uptake of iron was inhibited by cyanide and at higher concentrations by Ga. Furthermore, a K-M for iron uptake in cells of 2.36 mu M and a V-max of approximately 67 pmol Fe/min/mg protein was determined. [Fe-55]-uptake kinetics were measured in the absence and presence of Ga. Uptake of iron was inhibited merely at very high Ga concentrations. The results indicate an energy dependent iron uptake process in H. salinarum and suggest reduction of the metal at the membrane level.