NSF/BIO-DFG: Biological Fe-S intermediates in the synthesis of nitrogenase metalloclusters

NSF/BIO-DFG：固氮酶金属簇合成中的生物 Fe-S 中间体

• 批准号: 536145634
• 负责人: Professor Dr. Oliver Einsle
• 金额: --
• 依托单位: Institut für Biochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/536145634?language=en
• 关键词: NSF; BIO; DFG; Biological; Fe

Nitrogenase catalyzes the biological conversion of N2 gas into NH4+, a critical step in the biogeochemical nitrogen cycle. Despite its importance for life on Earth, nitrogen fixation is a trait limited to a subset of microbes, and the capacity to fix N2 is complex in mechanism, genetics, and regulation. The activity of nitrogenase depends on factors involved in the synthesis of its associated metallocofactors and on metabolic conditions that support this highly endergonic reaction. Therefore, defining the reactions performed by these factors has intrinsic intellectual merit and helps to understand their evolution. It is significant for developing sustainable, energy-saving strategies to produce nitrogen-based food crop supplements. This proposal aims to elucidate initial reaction steps involve the synthesis of Fe-S clusters destined for nitrogenase that are promoted by NifU and NifS. The presence of NifU and NifS is dominant in other aerobic nitrogen-fixing microbes, suggesting the requirement of a dedicated Fe-S cluster biosynthesis system for sustaining nitrogen fixation exactly then. In the model bacterium Azotobacter vinelandii, NifUS is required for nitrogen fixation by any of the three nitrogenase isoforms (Nif, Anf, and Vnf). Our preliminary data now show a previously uncharacterized cluster species on NifU when expressed in its native organism, A. vinelandii. We also show that Fpr2 is a suitable physiological reductant enabling for the first time the detection of novel, EPR-active species associated with NifU. We hypothesize that this transient cluster species represents a functional intermediate in the synthesis of nitrogenase metalloclusters. The research plan is aimed at investigating the mechanistic and chemical steps of Fe-S cluster synthesis by establishing 1) the location and spectroscopic features of novel cluster species associated with NifU, 2) the involvement additional factors in this process, and 3) the reactivity of the new cluster species as building blocks for the synthesis of nitrogenase metalloclusters. Defining the molecular and evolutionary details that enable nitrogen fixation has a prospect for a major agronomic, economic, and environmental impact. These principles can also guide foundational studies on Fe-S clusters on more complex systems not limited to nitrogen fixation. The interdisciplinary, collaborative international project will engage undergraduate and graduate students through research experiences and professional development opportunities. A German and an American PI partnership will support two synergistic research and professional development efforts: (a) collaborative research experiences abroad for graduate students; and (b) mentored research fellowships for local undergraduate students.

氮酶催化N2气体到NH4+的生物学转化，这是生物地球化学氮循环中的关键步骤。尽管对地球上的生命重要性，但氮的固定性却限于微生物的一部分，并且固定N2的能力在机制，遗传学和调节方面很复杂。氮酶的活性取决于与其相关金属生产子合成的因素以及支持这种高度端主反应的代谢条件。因此，定义这些因素执行的反应具有内在的智力优点，并有助于理解它们的进化。这对于制定可持续的节能策略来生产基于氮的粮食作物补充剂很重要。该建议旨在阐明初始反应步骤涉及由NIFU和NIFS促进的氮气中的Fe-S簇的合成。 NIFU和NIFS的存在在其他有氧氮固定微生物中占主导地位，这表明需要专用的Fe-S簇生物合成系统，以便当时准确维持氮固定。在模型杀菌杆菌的模型中，三种氮酶同工型（NIF，ANF和VNF）中的任何一个都需要氮固定氮。我们的初步数据现在显示了在其本机生物A. vinelandii中表达的Nifu上以前未表征的簇。我们还表明，FPR2是首次检测与NIFU相关的新型EPR活性物种的合适生理还原剂。我们假设这种瞬时簇种代表合成氮酶金属群的合成中的功能中间体。该研究计划旨在通过建立与NIFU相关的新型簇种的位置和光谱特征来研究Fe-S簇合成的机械和化学步骤，2）涉及此过程中的其他因素，以及3）新群集物种作为硝基质量酶金属酶合成的组合物的反应性。定义能够固定氮的分子和进化细节，可以对重大的农艺，经济和环境影响产生前景。这些原理还可以指导对不限于氮固定的更复杂系统的Fe-S簇的基础研究。跨学科的协作国际项目将通过研究经验和专业发展机会与本科生和研究生。德国和美国的PI合作伙伴关系将支持两项协同研究和专业发展工作：（a）在国外为研究生提供协作研究经验； （b）为当地本科生的指导研究奖学金。