Rapid evolution of a bacterial iron acquisition system.
Rapid evolution of a bacterial iron acquisition system.
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DOI：
10.1111/mmi.13918
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发表时间：
2018-04
影响因子：
3.6
通讯作者：
O'Brian MR
中科院分区：
文献类型：
--
作者：
Chatterjee A;O'Brian MR
在铁限制下，细菌从环境中吸收与铁载体或其他螯合物结合的三价铁（Fe 3+）以满足其营养需求。在革兰氏阴性细菌中，铁载体摄取系统原型由外膜转运蛋白、周质结合蛋白和细胞质膜转运蛋白组成，每种转运蛋白对单个铁载体或铁载体家族具有特异性。在这里，我们表明，自发的单一功能获得性错义突变外膜转运蛋白基因的慢生根瘤菌是足够的，赋予细胞使用合成或天然铁载体的能力，这表明选择性主要限于外膜，可以很容易地修改。此外，在天然或合成螯合剂上生长需要细胞质膜亚铁（Fe 2+）铁转运体FeoB，这表明铁在进入细胞质之前既从螯合物中解离又在周质内还原为亚铁形式。这些数据表明，快速适应环境铁的选择性外膜转运蛋白基因的突变和非选择性吸收组件，不需要突变，以适应新的铁源。与E.大肠杆菌，选择性吸收营养铁螯合物是有限的外膜慢生根瘤菌。编码外膜转运蛋白的基因中的功能获得突变足以允许B。日本根瘤菌适应环境中新的铁源。
Under iron limitation, bacteria scavenge ferric (Fe3+) iron bound to siderophores or other chelates from the environment to fulfill their nutritional requirement. In gram-negative bacteria, the siderophore uptake system prototype consists of an outer membrane transporter, a periplasmic binding protein, and a cytoplasmic membrane transporter, each specific for a single ferric siderophore or siderophore family. Here, we show that spontaneous single gain-of-function missense mutations in outer membrane transporter genes of Bradyrhizobium japonicum were sufficient to confer on cells the ability to use synthetic or natural iron siderophores, suggesting that selectivity is limited primarily to the outer membrane and can be readily modified. Moreover, growth on natural or synthetic chelators required the cytoplasmic membrane ferrous (Fe2+) iron transporter FeoB, suggesting that iron is both dissociated from the chelate and reduced to the ferrous form within the periplasm prior to cytoplasmic entry. The data suggest rapid adaptation to environmental iron by facile mutation of selective outer membrane transporter genes and by non-selective uptake components that do not require mutation to accommodate new iron sources. Unlike E. coli, selectivity for uptake of nutritional iron chelates is limited to the outer membrane in Bradyrhizobium japonicum. Gain-of-function mutations in genes encoding outer membrane transporters are sufficient to allow B. japonicum to readily adapt to new iron sources in the environment.
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影响因子：
3.5
作者：
Braun, Volkmar;Pramanik, Avijit;Gwinner, Thomas;Koeberle, Martin;Bohn, Erwin
通讯作者：
Bohn, Erwin
影响因子：
--
作者：
D'Onofrio A;Crawford JM;Stewart EJ;Witt K;Gavrish E;Epstein S;Clardy J;Lewis K
通讯作者：
Lewis K
影响因子：
4.1
作者：
Kaneko, T;Nakamura, Y;Tabata, S
通讯作者：
Tabata, S
影响因子：
3.2
作者：
Escamilla-Hernandez, Rosalba;O'Brian, Mark R.
通讯作者：
O'Brian, Mark R.
影响因子：
3.6
作者：
Gu, Mianzhi;Imlay, James A.
通讯作者：
Imlay, James A.