Directly quantifying the isotopic fractionation associated with the key enzymes in microbial sulfate reduction

直接量化与微生物硫酸盐还原中关键酶相关的同位素分级分离

• 批准号: 1225980
• 负责人: David Johnston
• 金额: $ 23.92万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2015-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1225980&HistoricalAwards=false
• 关键词: Directly; quantifying; isotopic; fractionation; associated

The microbial lifestyle of sulfate reduction is central to the oxidation of organic matter both in the Modern and throughout Earth?s history. This linkage to the carbon cycle, and in turn climate, is commonly inferred through sulfur isotope studies, which are themselves informed by experiments with extant bacteria that perform this process. At its core, however, bacteria are driven by a suite of enzymes, or catalysts, that conduct much of the critical chemistry. In this proposal, investigators look to place the first direct isotopic constraints on the two key enzymatic steps within this metabolism: dissimilatory sulfite reductase [DsrAB/C] and APS oxido-reductase [APSr]. This data will allow for a more mechanistic understanding of cellular fractionation processes, which will then sharpen our capacity to read environmental records.This research project will be conducted in collaboration with Dr. Ines Pereira of the Instituto De Technologia Quimica E Biologica, ITQB, Portugal, who will provide the biochemistry expertise necessary for the project. A Harvard graduate student will travel between the Pereira and Johnston's labs, acquiring valuable interdisciplinary training in isotope geochemistry and biochemistry. Travel costs for the international component of this research have been provided by the NSF Office of International Science and Engineering.

硫酸盐还原的微生物生活方式对于现代和整个地球历史中的有机物氧化至关重要。 这种与碳循环乃至气候的联系通常是通过硫同位素研究推断出来的，硫同位素研究本身是通过对执行这一过程的现存细菌进行的实验得出的。 然而，从本质上讲，细菌是由一系列酶或催化剂驱动的，这些酶或催化剂负责大部分关键化学反应。 在该提案中，研究人员希望首次对该代谢中的两个关键酶促步骤施加直接同位素限制：异化亚硫酸盐还原酶 [DsrAB/C] 和 APS 氧化还原酶 [APSr]。 这些数据将使我们能够更机械地理解细胞分离过程，从而提高我们读取环境记录的能力。该研究项目将与葡萄牙 ITQB Quimica E Biologica 技术研究所的 Ines Pereira 博士合作进行，谁将提供该项目所需的生物化学专业知识。一名哈佛大学研究生将往返于佩雷拉和约翰斯顿的实验室之间，获得同位素地球化学和生物化学方面宝贵的跨学科培训。这项研究的国际部分的旅费由美国国家科学基金会国际科学与工程办公室提供。