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A new pathway for iron-sulfur cluster repair

铁硫簇修复的新途径

基本信息

批准号：
BB/L007673/1
负责人：
Nicolas Le Brun
金额：
$ 45.95万
依托单位：
University of East Anglia
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FL007673%2F1
关键词：
new pathway iron sulfur cluster

项目摘要

Bacteria inhabit almost every environmental niche on Earth, including some that are so harsh that many other forms of life cannot survive. This success is at least in part due to the ability of bacteria to adapt to changes in environment, and this adaptation is rooted in their capacity to alter patterns of gene expression in response to external and internal cues. A key environmental parameter that is monitored by many bacteria is oxygen concentration. We are particularly interested in the bacterium Escherichia coli (E. coli). One of its remarkable properties is that it is able to thrive both in the presence and absence of oxygen. To do this it has to dramatically alter its metabolism, but this has consequences because without oxygen the potential for energy conservation and growth are limited compared to when oxygen is present. To test whether oxygen is present E. coli uses a protein called FNR, which acts as an oxygen sensor. It has a special co-factor called an iron-sulfur cluster that reacts with oxygen in a way that switches FNR off. This involves the conversion of the cluster from one form (called the [4Fe-4S] form) to another (called the [2Fe-2S] form). In the 'off-state' FNR is in its [2Fe-2S] form and cannot bind to DNA to activate expression of genes that are used during growth in the absence of oxygen. When there is no oxygen the iron-sulfur cluster remains in the [4Fe-4S] form and the protein can bind to DNA and activate expression of genes that are needed for growth in the absence of oxygen.For the last few years we have studied the reaction of oxygen with the FNR iron-sulfur cluster. These studies have revealed the complex biochemistry of the reaction and how this makes the FNR protein an exquisitely sensitive oxygen sensor. We recently showed that in its 'off-state' the [2Fe-2S] cluster is different from most other previously characterised [2Fe-2S] cluster cofactors and that this is a result of the fact that it is formed through oxidative conversion (which can be thought of as oxidative damage) of the [4Fe-4S] form. This results in an unusual modification of the protein in which sulfide from the initial [4Fe-4S] cluster is attached to the protein during the conversion reaction. This can be thought of as a form of stored sulfur and, remarkably, this can be used to repair the cluster back to its original [4Fe-4S] form when oxygen is no longer present. The unusual [2Fe-2S] cluster of FNR has also been discovered in other iron-sulfur cluster proteins, raising the possibility that repair of oxidatively damaged [4Fe-4S] clusters via this mechanism might be widespread.Using a wide range of approaches, we propose to investigate further the formation of the unusual [2Fe-2S] cluster and the repair of [4Fe-4S] cluster to determine the mechanism and the importance of this in vivo as a previously unrecognised pathway for repair of oxidatively damaged iron-sulfur clusters.

细菌几乎存在于地球上的每一个环境中，包括一些非常恶劣的环境，以至于许多其他形式的生命无法生存。这一成功至少部分归功于细菌适应环境变化的能力，而这种适应植根于它们对外部和内部线索做出反应而改变基因表达模式的能力。许多细菌监测的一个关键环境参数是氧气浓度。我们特别感兴趣的是细菌大肠杆菌(E.coli)。它的显著特性之一是在有氧和无氧的情况下都能茁壮成长。要做到这一点，它必须极大地改变自己的新陈代谢，但这会产生后果，因为与有氧气存在时相比，没有氧气，能量守恒和生长的潜力是有限的。为了测试是否存在氧气，大肠杆菌使用了一种名为FNR的蛋白质，它起到了氧气传感器的作用。它有一种特殊的辅助因子，称为铁-硫簇，它与氧气发生反应，关闭FNR。这涉及到团簇从一种形式(称为[4Fe-4S]形式)到另一种形式(称为[2Fe-2S]形式)的转换。在‘关闭’状态下，FNR以[2Fe-2S]形式存在，不能与DNA结合来激活在无氧生长过程中使用的基因的表达。当没有氧气时，铁-硫簇仍然以[4Fe-4S]形式存在，蛋白质可以与DNA结合，并在没有氧的情况下激活生长所需基因的表达。在过去的几年里，我们研究了氧与FNR铁-硫簇的反应。这些研究揭示了反应的复杂生物化学，以及这是如何使FNR蛋白成为一种极其敏感的氧传感器的。我们最近发现，在关闭状态下，[2Fe-2S]团簇不同于大多数其他以前表征的[2Fe-2S]团簇辅助因子，这是因为它是通过[4Fe-4S]形式的氧化转化(可以被认为是氧化损伤)形成的。这导致了蛋白质的一种不寻常的修饰，在转化反应中，来自初始[4Fe-4S]簇的硫化物附着在蛋白质上。这可以被认为是一种储存的硫，值得注意的是，当氧不再存在时，这可以用来将星团修复回其原始的[4Fe-4S]形式。在其他铁-硫簇蛋白中也发现了异常的FNR[2Fe-2S]簇，这增加了通过这种机制修复氧化损伤的[4Fe-4S]簇的可能性。我们建议使用广泛的方法，进一步研究异常[2Fe-2S]簇的形成和[4Fe-4S]簇的修复，以确定这是一种在体内作为先前未知的修复氧化损伤铁硫簇的途径的机制和重要性。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Differentiated, Promoter-specific Response of [4Fe-4S] NsrR DNA Binding to Reaction with Nitric Oxide.

DOI：
10.1074/jbc.m115.693192
发表时间：
2016-04-15
期刊：
The Journal of biological chemistry
影响因子：
0
作者：
Crack JC;Svistunenko DA;Munnoch J;Thomson AJ;Hutchings MI;Le Brun NE
通讯作者：
Le Brun NE

NsrR from Streptomyces coelicolor is a nitric oxide-sensing [4Fe-4S] cluster protein with a specialized regulatory function.

DOI：
10.1074/jbc.m115.643072
发表时间：
2015-05-15
期刊：
The Journal of biological chemistry
影响因子：
0
作者：
Crack JC;Munnoch J;Dodd EL;Knowles F;Al Bassam MM;Kamali S;Holland AA;Cramer SP;Hamilton CJ;Johnson MK;Thomson AJ;Hutchings MI;Le Brun NE
通讯作者：
Le Brun NE

The Di-Iron Protein YtfE Is a Nitric Oxide-Generating Nitrite Reductase Involved in the Management of Nitrosative Stress.

DOI：
10.1021/jacs.1c12407
发表时间：
2022-04-27
期刊：
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
影响因子：
15
作者：
Crack, Jason C.;Balasiny, Basema K.;Bennett, Sophie P.;Rolfe, Matthew D.;Froes, Afonso;MacMillan, Fraser;Green, Jeffrey;Cole, Jeffrey A.;Le Brun, Nick E.
通讯作者：
Le Brun, Nick E.

Biochemical properties of Paracoccus denitrificans FnrP: reactions with molecular oxygen and nitric oxide.