Sulfido dithiolene complexes modeling molybdenum and tungsten dependent oxiodreductases - investigating synthesis, catalysis and biological activity to elucidate structural uncertainties, structure-function relationships and biosynthesis

磺基二硫烯配合物模拟钼和钨依赖性氧化还原酶 - 研究合成、催化和生物活性，以阐明结构不确定性、结构-功能关系和生物合成

• 批准号: 310986441
• 负责人: Professorin Dr. Carola Schulzke
• 金额: --
• 依托单位: Arbeitskreis Bioanorganische Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/310986441?language=en
• 关键词: Sulfido; dithiolene; complexes; modeling; molybdenum

Iron-sulfur cluster are critically important for the biosynthesis and function of essential molybdenum and tungsten oxidoreductases. Crucial aspects will be investigated of the maturation and catalytic activity of molybdenum and tungsten co-factors, being directly dependent on FeS cluster proteins (keyword: crosstalk). A better understanding of the respective enzymes and their synergy shall be facilitated by chemical model syntheses, spectroscopic characterization, catalytic and kinetic evaluation and the biological interaction with proteins (chaperones/apo-enzymes). Important issues specifically concern the role of the sulfido ligand in the Mo and W active sites, which is introduced/transferred in vivo by IscS. Sulfido coordination and its function for the enzymes’ reactivity in particular, will be chemically studied on model compounds. The catalytic mechanisms will be elucidated and all analytical results used to competently discriminate between actual and artefactual presence of this sulfido ligand in the active sites of respective enzymes (in some of which its presence being not unambiguously clear). Isotopically labelling the sulfido ligand in model complexes selectively will further the respective required insight. Highly developed ligand systems, having recently been shown to induce binding to natural proteins, will have significant impact in this context and further the understanding of cellular processes; in particular of sulfur transfer and insertion, which is specifically relevant for the dithiolene-derived molybdopterin (MPT) ligands and sulfido coordination. Sophisticated mono-oxido bis-dithiolene complexes of molybdenum (and tungsten), mimicking various aspects of natural MPT, shall be modified by exchanging sulfido (=S) for oxido (=O) ligation for which the application of bis-carbonyl precursors was established as the most feasible procedure. Electrochemical oxidation and the concomitant presence of SH– ions will be investigated for the synthesis of MVIOS species. The synthesis of azide dithiolene molybdenum complexes constitutes another important aim. Such complexes are needed for elucidating the inhibition of Mo-dependent E. coli formate dehydrogenase (FDH) by comparison of enzymatic and model complex spectroscopic data. Being isoelectronic to the enzymatic product CO2, azide binding to protein will serve the understanding of FDH’s reaction mechanism, which again has implications for CO2 chemistry. Comprehensively characterising all synthesised complexes spectroscopically, studying their catalytic potential and the kinetics of such reactions plus investigating their biological activity will provide intimate insight into nature’s strategies to foster reactivity and concomitant stability. The biological activity will be assessed by investigating specific binding to proteins, which participate in molybdenum or tungsten cofactor maturation, as well as to apoenzymes and the catalytic activity of respective semi-synthetic enzymes.

铁硫簇对于必需的钼和钨氧化还原酶的生物合成和功能至关重要，将研究直接依赖于 FeS 簇蛋白的钼和钨辅助因子的成熟和催化活性（关键词：串扰）。通过化学模型合成、光谱表征，可以促进对各种酶及其协同作用的更好理解。催化和动力学评估以及与蛋白质（分子伴侣/载脂蛋白酶）的生物相互作用特别涉及硫基配体在Mo和W活性位点中的作用，其通过IscS在体内引入/转移。特别是酶反应性的功能，将在模型化合物上进行化学研究，并阐明催化机制，并使用所有分析结果来有效地区分实际存在和人造存在。在模型复合物中选择性地同位素标记硫代配体将进一步深入了解高度发达的配体系统，其中一些酶的活性位点中其存在并不明确。诱导与天然蛋白质的结合，将在这方面产生重大影响，并进一步了解细胞过程，特别是硫转移和插入，这与二硫烯衍生的钼蝶呤特别相关； (MPT) 配体和硫基配位 复杂的钼（和钨）单氧化双二硫烯配合物，模拟天然 MPT 的各个方面，应通过将硫基 (=S) 替换为氧化 (=O) 连接来进行修饰。双羰基前体的应用被确定为最可行的程序，并且伴随的 SH- 离子的存在。研究了叠氮二硫烯钼复合物的合成，这是通过比较酶学和模型复合物光谱数据来阐明对钼依赖性大肠杆菌甲酸脱氢酶（FDH）的抑制作用所需要的。叠氮化物与酶产物 CO2 等电子，与蛋白质结合将有助于理解 FDH 的反应机制，这再次对 CO2 产生影响全面表征所有合成的复合物的光谱、研究其催化潜力和此类反应的动力学以及研究其生物活性将提供对促进反应性和伴随稳定性的自然策略的深入了解。生物活性将通过研究与蛋白质的特异性结合来评估。 ，其参与钼或钨辅因子的成熟，以及脱辅基酶和相应半合成酶的催化活性。