Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
Appl Environ Microbiol. 2018 Oct 1;84(20). doi: 10.1128/AEM.01752-18. Print 2018 Oct 15.
is an extensively studied bacterium capable of respiring minerals, including a variety of iron ores, as terminal electron acceptors (EAs). Although iron plays an essential and special role in iron respiration of , little has been done to date to investigate the characteristics of iron transport in this bacterium. In this study, we found that all proteins encoded by the cluster for putrebactin ( native siderophore) synthesis (PubABC), recognition-transport of Fe-putrebactin across the outer membrane (PutA), and reduction of ferric putrebactin (PutB) are essential to putrebactin-mediated iron uptake. Although homologs of PutA are many, none can function as its replacement, but some are able to work with other bacterial siderophores. We then showed that Fe-specific Feo is the other primary iron uptake system, based on the synthetical lethal phenotype resulting from the loss of both iron uptake routes. The role of the Feo system in iron uptake appears to be more critical, as growth is significantly impaired by the absence of the system but not of putrebactin. Furthermore, we demonstrate that hydroxyl acids, especially α-types such as lactate, promote iron uptake in a Feo-dependent manner. Overall, our findings underscore the importance of the ferrous iron uptake system in metal-reducing bacteria, providing an insight into iron homeostasis by linking these two biological processes. is among the first- and the best-studied metal-reducing bacteria, with great potential in bioremediation and biotechnology. However, many questions regarding mechanisms closely associated with those applications, such as iron homeostasis, including iron uptake, export, and regulation, remain to be addressed. Here we show that Feo is a primary player in iron uptake in addition to the siderophore-dependent route. The investigation also resolved a few puzzles regarding the unexpected phenotypes of the mutant and lactate-dependent iron uptake. By elucidating the physiological roles of these two important iron uptake systems, this work revealed the breadth of the impacts of iron uptake systems on the biological processes.
是一种被广泛研究的细菌，能够以多种铁矿石等矿物作为末端电子受体进行呼吸。虽然铁在的铁呼吸中起着至关重要和特殊的作用，但迄今为止，对这种细菌中铁的转运特性的研究甚少。在本研究中，我们发现，与腐胺（天然铁载体）合成（PubABC）、Fe-腐胺穿过外膜的识别-转运（PutA）和三价腐胺还原（PutB）相关的簇编码的所有蛋白都是腐胺介导的铁吸收所必需的。尽管 PutA 的同源物很多，但没有一种能够替代它，而有些则能够与其他细菌的铁载体一起发挥作用。然后，我们基于两条铁吸收途径的丧失导致合成致死表型，表明 Fe 特异性的 Feo 是另一个主要的铁吸收系统。Feo 系统在铁吸收中的作用似乎更为关键，因为该系统的缺失会显著影响生长，而不是腐胺的缺失。此外，我们证明羟基酸，特别是α 型如乳酸，以 Feo 依赖的方式促进铁的吸收。总的来说，我们的研究结果强调了亚铁吸收系统在金属还原细菌中的重要性，通过将这两个生物学过程联系起来，为铁稳态提供了新的认识。是研究最早、研究最深入的金属还原细菌之一，在生物修复和生物技术方面具有巨大的潜力。然而，许多与这些应用密切相关的机制问题，如铁稳态，包括铁的吸收、输出和调节，仍有待解决。在这里，我们表明，除了依赖铁载体的途径外，Feo 也是铁吸收的主要参与者。该研究还解决了有关突变体和乳酸依赖铁吸收的意外表型的一些难题。通过阐明这两个重要铁吸收系统的生理作用，这项工作揭示了铁吸收系统对生物过程的广泛影响。
