Spectroscopic Studies of Molybdenum and Tungsten Enzymes

钼和钨酶的光谱研究

• 批准号: RGPIN-2014-04632
• 负责人: George, Graham
• 金额: $ 3.93万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=632529
• 关键词: Spectroscopic; Studies; Molybdenum; Tungsten; Enzymes

Transition metal ions are integral to a large number of enzymes and other proteins, with transition metalloproteins constituting about 11% of a typical organism’s genomic output. Transition metal ions are used by the enzymes to catalyze many of the most chemically challenging and industrially relevant reactions carried out by living organisms. Among all of the transition metals employed by living things, molybdenum and tungsten are distinguished as being the only second-row and third-row transition elements with a known function in life. Tungsten is further distinguished as the heaviest element known to have functional roles in biology. The structures of molybdenum and tungsten enzymes are very closely related, both containing an unusual sulfur-containing organic cofactor called molybdopterin. The roles of molybdenum and tungsten in metalloenzymes often appear to be interchangeable, with molybdenum enzymes found broadly in higher organisms, while the role of molybdenum is filled by tungsten in more primitive organisms. Together, the molybdenum and tungsten enzymes have important roles in almost all living organisms, from archaea to bacteria through plants to invertebrates and mammals. They do this within enzyme active sites that, while sharing common structural motifs such as the molybdopterin, are remarkable in the range of different chemical reactions are catalyzed. The functional roles fulfilled by the enzymes are equally diverse; for example, they play essential roles in microbial respiration, in the uptake of nitrogen in green plants, in controlling insect eye color, and in human health. The tungsten enzymes are thought to have played important roles in early life on earth, most notably in the organism known as the LUCA (last universal common ancestor), sometimes called the cenancestor, the progenitor of all earthly life now extant.The proposed work is a systematic study of the major families of molybdenum and tungsten enzymes using a combination of synchrotron-based and computational chemistry methods. We propose to further develop a novel holistic approach in combining information from X-ray absorption spectroscopy, advanced computer molecular modeling, and crystal structures to obtain the most accurate picture yet of the active sites, and thereby to elucidate their detailed catalytic mechanisms. The ultimate goal of the work is thus to develop an in-depth quantitative structural and electronic understanding of the catalytic mechanisms used by the enzymes, comparing and contrasting between and within the different families. This will lead to a richer understanding of how molybdenum and tungsten enzymes achieve their remarkable functional diversity. The benefits of this research are four-fold: (i) The results will yield detailed insights for an important group of enzymes. (ii) The holistic approach and the methods developed for it will be broadly applicable to studies of any metalloprotein. (iii) The results will provide insights into a group of enzymes that were important in primordial life on earth. (iv) By driving and developing techniques at the Canadian Light Source, the research will strengthen the opportunity for Canadian researchers to utilize these synchrotron tools in structural molecular biology.

过渡金属离子是大量酶和其他蛋白质的组成部分，其中过渡金属蛋白质占典型生物体基因组输出的约11%。过渡金属离子被酶用于催化许多由生物体进行的最具化学挑战性和工业相关的反应。在生物所使用的所有过渡金属中，钼和钨被认为是唯一在生命中具有已知功能的第二行和第三行过渡元素。钨被进一步区分为已知在生物学中具有功能作用的最重元素。钼和钨酶的结构非常密切相关，都含有一种不寻常的含硫有机辅因子，称为钼蝶呤。钼和钨在金属酶中的作用似乎可以互换，钼酶广泛存在于高等生物中，而钼的作用在更原始的生物中由钨填充。钼和钨酶一起在几乎所有生物体中发挥重要作用，从古细菌到细菌，再到植物，再到无脊椎动物和哺乳动物。它们在酶活性位点内这样做，虽然共享共同的结构基序，如异蝶呤，但在催化不同化学反应的范围内是显着的。这些酶的功能作用也是多种多样的，例如，它们在微生物呼吸、绿色植物的氮吸收、控制昆虫眼睛颜色和人类健康中发挥重要作用。钨酶被认为在地球早期生命中发挥了重要作用，最显著的是在被称为LUCA（最后的普遍共同祖先）的有机体中，有时也被称为cenancestor，现在现存的所有地球生命的祖先。拟议的工作是使用基于同步加速器和计算化学方法的组合对钼和钨酶的主要家族进行系统研究。我们建议进一步开发一种新的整体方法，结合X射线吸收光谱，先进的计算机分子建模和晶体结构的信息，以获得最准确的图片活性位点，从而阐明其详细的催化机制。因此，这项工作的最终目标是对酶所使用的催化机制进行深入的定量结构和电子理解，比较和对比不同家族之间的差异。这将导致更丰富的了解钼和钨酶如何实现其显着的功能多样性。这项研究的好处有四个方面：（i）结果将为一组重要的酶提供详细的见解。(ii)整体的方法和开发的方法，它将广泛适用于任何金属蛋白的研究。(iii)这些结果将为了解一组在地球原始生命中非常重要的酶提供帮助。(iv)通过推动和开发加拿大光源的技术，这项研究将加强加拿大研究人员在结构分子生物学中利用这些同步加速器工具的机会。