Nitrogen

氮

• 批准号: BB/L011468/1
• 负责人: Alfred Rutherford
• 金额: $ 105.12万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FL011468%2F1
• 关键词: Nitrogen

Nitrogen is most often the limiting nutrient to terrestrial ecosystems. Multiple bacterialand archaeal lineages have evolved the ability to fix atmospheric nitrogen, representing significant inputs to agronomic systems. This reaction is carried out by nitrogenase and is driven by ATP. All known nitrogenases are inhibited by oxygen, leading to specialized adaptations that limit intracellular free oxygen levels. There is one exception: an oxygen insensitive nitrogenase has that was isolated from a Streptomyces thermoautotrophicus found in soil above burning charcoal fires. This superoxide-dependent nitrogenase was partially characterized but the strain is no longer available. The present project seeks to re-isolate the original strain, as well as seek other O2-tolerant nitrogen-fixing strains from similar environments. These strains will then have their genomes sequenced and the biochemical and physiological properties of their nitrogenases studied in order to understand the O2 tolerance and to facilitate their transfer to other organisms.The discovery of the oxygen-tolerant superoxide-dependent nitrogenase in Streptomyces thermoautotrophicus was a remarkable result. It features in textbooks and reviews and yet there have been no primary publications on the subject since the original description in 1997. There is a good deal of speculation on why this is case, perhaps the most likely is that organism has been lost because of the difficulty of culturing cells in a carbon monoxide atmosphere. The rediscovery of this enzyme and/or other unknown enzymes with similar oxygen-insensitivity, makes this a high-risk but high-reward project. Solving the mystery of the lost enzyme is in itself a worthwhileintellectual task. If the outcome is positive and the O2-tolerant enzyme is re-isolated and/or other examples are discovered, this will open up important new avenues of research. Thus, this modest detective project could not only trigger a serious reappraisal of mainstream thinking about nitrogenase but also would transform major aspects of biological nitrogen fixation research.The rediscovery of the superoxide dependent nitrogenase and/or the discovery ofnovel oxygen-tolerant nitrogenases, followed by their genetic, biochemical, structural, and physiological characterization, is the ultimate goal of this project. We shall exploit the complementary expertise and the transatlantic nature of our new collaborative team, which was assembled at the Nitrogen 'Ideas Lab', to make a serious attempt at this bold endeavor. This high risk, high reward project is thus well-suited to this type of program call. If successful, this work has the potential to transform all areas of nitrogen-fixation research with both biological and industrial spin-offs. In particular, this would represent the first step towards the future goal of moving oxygen-tolerant nitrogenase systems into crop plants to alleviate terrestrial nitrogen limitation in a sustainable manner without negative environmental consequences.

氮通常是陆地生态系统的限制性营养物质。多种细菌和古细菌谱系已经进化出了固定大气氮的能力，这代表了农业系统的重要投入。该反应由氮酶进行，并由ATP驱动。所有已知的氮酶都受到氧气的抑制，导致限制细胞内自由氧水平的特殊适应。有一个例外：从燃烧木炭的土壤中发现的热自养链霉菌中分离出一种对氧不敏感的氮酶。这种依赖超氧化物的氮酶已被部分表征，但该菌株已不再可用。目前的项目旨在重新分离原始菌株，以及从类似环境中寻找其他耐o2固氮菌株。然后对这些菌株进行基因组测序，并研究其氮酶的生化和生理特性，以了解其对氧的耐受性，并促进其转移到其他生物体。在热自养链霉菌中发现耐氧超氧依赖的氮酶是一个显著的成果。它出现在教科书和评论中，但自1997年首次描述以来，就没有关于这一主题的主要出版物。关于为什么会出现这种情况，有很多猜测，也许最有可能的是，由于在一氧化碳的气氛中培养细胞的困难，生物体已经消失了。重新发现这种酶和/或其他具有类似氧不敏感性的未知酶，使这成为一个高风险但高回报的项目。解开丢失的酶之谜本身就是一项有价值的智力任务。如果结果是积极的，并且重新分离出耐氧酶和/或发现其他例子，这将开辟重要的新研究途径。因此，这个适度的探测项目不仅可以引发对氮酶主流思想的严肃重新评价，而且可以改变生物固氮研究的主要方面。重新发现超氧化物依赖的氮酶和/或发现新的耐氧氮酶，然后对其进行遗传、生化、结构和生理表征，是本项目的最终目标。我们将利用我们在氮气“创意实验室”组建的新合作团队的互补专业知识和跨大西洋性质，为这项大胆的努力做出认真的尝试。因此，这种高风险、高回报的项目非常适合这种类型的程序调用。如果成功，这项工作有可能通过生物和工业副产品改变固氮研究的所有领域。特别是，这将是迈向未来目标的第一步，即将耐氧氮酶系统转移到作物植物中，以可持续的方式减轻陆地氮的限制，而不产生负面的环境后果。

项目成果

Structural Basis for the Mechanism of ATP-Dependent Acetone Carboxylation.

• DOI: 10.1038/s41598-017-06973-8
• 发表时间: 2017-08-03
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Mus F;Eilers BJ;Alleman AB;Kabasakal BV;Wells JN;Murray JW;Nocek BP;DuBois JL;Peters JW
• 通讯作者: Peters JW

Streptomyces thermoautotrophicus does not fix nitrogen.

• DOI: 10.1038/srep20086
• 发表时间: 2016-02-01
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: MacKellar D;Lieber L;Norman JS;Bolger A;Tobin C;Murray JW;Oksaksin M;Chang RL;Ford TJ;Nguyen PQ;Woodward J;Permingeat HR;Joshi NS;Silver PA;Usadel B;Rutherford AW;Friesen ML;Prell J
• 通讯作者: Prell J

A low-potential terminal oxidase associated with the iron-only nitrogenase from the nitrogen-fixing bacterium Azotobacter vinelandii.

一种低电位末端氧化酶，与固氮细菌 Azotobacter vinelandii 的纯铁固氮酶相关。

• DOI: 10.1074/jbc.ra118.007285
• 发表时间: 2019
• 期刊: The Journal of biological chemistry
• 作者: Varghese F

Crystal structure of the [2Fe-2S] protein I (Shethna protein I) from Azotobacter vinelandii.

• DOI: 10.1107/s2053230x21009936
• 发表时间: 2021-11-01
• 期刊: Acta crystallographica. Section F, Structural biology communications
• 作者: Kabasakal BV;Cotton CAR;Murray JW
• 通讯作者: Murray JW

GlnK Facilitates the Dynamic Regulation of Bacterial Nitrogen Assimilation.

• DOI: 10.1016/j.bpj.2017.04.012
• 发表时间: 2017-05-23
• 期刊: Biophysical journal
• 影响因子: 3.4
• 作者: Gosztolai A;Schumacher J;Behrends V;Bundy JG;Heydenreich F;Bennett MH;Buck M;Barahona M
• 通讯作者: Barahona M