Biochemical and electrochemical characterization of redox protein candidates of the iron oxidation in the acidophilic iron oxidizer “Ferrovum” sp. PN-J47-F6

嗜酸性铁氧化剂“Ferrovum” sp 中铁氧化的氧化还原蛋白候选物的生化和电化学表征。

• 批准号: 413029825
• 负责人: Dr. Sophie Ullrich
• 金额: --
• 依托单位: Arbeitsgruppe Biologie / Ökologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/413029825?language=en
• 关键词: Biochemical; electrochemical; characterization; redox; protein

Aerobic iron oxidizing organisms coupling ferrous iron oxidation to the reduction of oxygen cope with life at the thermodynamic limit due to the extremely low redox potential difference between the electron donor (ferrous/ferric iron) and acceptor couple (oxygen/water). Since external pH also effects the redox potential of the electron donor and acceptor couple and, thereby, the energy yield of the electron transfer process, it has been postulated that the biochemical properties of redox proteins involved in iron oxidation are also effected by the external pH of the habitat. However, biochemical studies on redox proteins of iron oxidizers are limited to few model organisms (Acidithiobacillus ferrooxidans, Ferroplasma acidiphilum). Nevertheless, omics-based research allowed the prediction of electron transfer chains in several prokaryotes. Among Betaproteobacteria there are both acidophilic iron oxidizers, such as “Ferrovum” spp. and neutrophilic iron oxidizers. In comparison to model acidophiles members of the genus “Ferrovum” are more moderate acidophiles. A model of the iron oxidation in “Ferrovum” spp. was inferred by genome analysis and extended based on transcriptome data. Intriguingly, redox proteins of the predicted iron oxidation model share more similarities with those of neutrophilic iron oxidizers belonging to the Beta- and Zetaproteobacteria than with those of other acidophiles.Hence, “Ferrovum” spp. present a unique model to investigate whether biochemical properties of iron oxidation proteins have adapted to the lower external pH. Therefore, the proposed project aims to investigate the phylogeny of the protein candidates of the iron oxidation model and to characterize their biochemical properties. Aim (i) will be approached bioinformatically: Dendrograms of these redox proteins will be calculated and then be compared to dendrograms based on taxonomic markers (i.e. 16S rRNA gene sequence). Aim (ii) will be approached at two levels. First, selected soluble protein candidates of “Ferrovum” sp. PN-J47-F6 will be produced heterologously for biochemical and electrochemical characterization in order to identify their redox centers and to determine their mid-point potential. Protein-protein interaction studies are planned to elucidate the proposed electron transfer chain of the iron oxidation model. The second level involves biochemical and electrochemical characterization of wild type proteins in membrane fractions of “Ferrovum” sp. PN-J47-F6. Therefore, biochemical properties of the recombinant proteins are intended to be used as reference. The proposed study will amend our current knowledge on microbial iron oxidation by providing the first biochemical data on redox proteins involved in iron oxidation in a moderate acidophile. This data may allow valuable insights into how evolution of this energy conserving process has been influenced by external pH of the habitat.

好氧铁氧化生物体将亚铁氧化与氧的还原结合起来科普由于电子供体（亚铁/三价铁）和受体对（氧/水）之间极低的氧化还原电位差，它们在热力学极限下应对生命。由于外部pH值也影响电子供体和受体对的氧化还原电位，从而影响电子转移过程的能量产率，因此推测参与铁氧化的氧化还原蛋白的生物化学性质也受到栖息地外部pH值的影响。然而，铁氧化剂的氧化还原蛋白的生化研究仅限于少数模式生物（嗜酸氧化亚铁硫杆菌，嗜酸铁浆菌）。然而，基于组学的研究允许在几个原核生物中预测电子转移链。在β-变形菌中，有两种嗜酸性铁氧化剂，如“Ferrovum”spp。和亲水铁氧化剂。与模式嗜酸菌相比，“Ferrovum”属的成员是更温和的嗜酸菌。一个铁氧化的“Ferrovum”spp。通过基因组分析推断，并基于转录组数据进行扩展。有趣的是，预测的铁氧化模型的氧化还原蛋白与属于β-和Zetaproteobacteria的嗜酸性铁氧化剂的氧化还原蛋白比与其他嗜酸菌的氧化还原蛋白具有更多的相似性。提出了一个独特的模型，以调查铁氧化蛋白的生化特性是否已适应较低的外部pH值。因此，拟议的项目旨在调查铁氧化模型的蛋白候选物的生物化学特性，并表征其生化特性。目标（i）将采用生物信息学方法：计算这些氧化还原蛋白的树状图，然后将其与基于分类标记（即16 S rRNA基因序列）的树状图进行比较。将在两个层面上实现目标（ii）。首先，选择的可溶性蛋白候选物的“Ferrovum”sp. PN-J 47-F6将产生异源的生化和电化学表征，以确定其氧化还原中心，并确定其中点电位。蛋白质-蛋白质相互作用的研究计划，以阐明所提出的电子转移链的铁氧化模型。第二个层次涉及的生物化学和电化学特性的野生型蛋白质的膜馏分的“铁”sp. PN-J 47-F6。因此，重组蛋白的生物化学性质旨在用作参考。拟议的研究将修正我们目前的知识，微生物铁氧化提供的第一个生化数据氧化还原蛋白参与铁氧化在一个温和的嗜酸菌。这些数据可以让有价值的见解如何进化的这种节能过程受到外部pH值的栖息地。