Collaborative Research: Elucidating the Influence of Metal Binding on Electronic/Geometric Structure-Function Relationships in Photorespiration

合作研究：阐明金属结合对光呼吸中电子/几何结构-功能关系的影响

• 批准号: 1904310
• 负责人: Kyle Lancaster
• 金额: $ 44.5万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1904310&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; Influence; Metal

In this project funded by the Chemistry of Life Processes Program of the Chemistry Division, Professors Kyle M. Lancaster of the Cornell University and Arnold J. Bloom of the University of California Davis evaluate the role of differential metal binding, specifically magnesium versus manganese, on the mechanisms and bioenergetics of photorespiration in which Rubisco, the most prevalent protein on the planet, reacts with oxygen rather than with carbon dioxide. This collaboration between a bioinorganic spectroscopist and a plant physiologist seeks to provide new perspectives on the evolution of photosynthesis and the relationships between plant carbon and nitrogen balances under past, present, and future environmental conditions. Such information is critical for maintaining food quality and ensuring world food security in the coming decades. Professors Lancaster and Bloom disseminate this information through articles in the online Encyclopedia of Earth, workshops at scientific meetings, including some organized by Societies of scientists who are members of groups underrepresented in STEM careers, and by writing and keeping up-to-date printed and online textbooks used by students as well as by American and foreign professionals whose work is related to environmental change. The proposed research involves application of a broad range of spectroscopic, kinetics, and computational techniques to contrast protein structure and plant metabolism when manganese or magnesium binds to the enzymes that catalyze the first three chemical steps in the photorespiratory pathway. The Mn2+-bound forms of Rubisco, malic enzyme, and phosphoglycolate phosphatase are characterized by X-ray crystallography and by electron spin resonance, X-ray absorption, and magnetic circular dichroism spectroscopy. Both isolated, intact chloroplasts as well as purified photorespiratory enzymes are studied. The work with isolated chloroplasts involves ratiometric dye measurements of magnesium and manganese concentrations, optode measurements of O2 and CO2 consumption, and mass spectrometric assessment of photorespiratory products. Work carried out on isolated enzymes involves measurement of electron transfer kinetics from manganese Rubisco during oxygenation of ribulose-1,5-bisphosphate as well as investigation of potential physiologically relevant electron transfer partners. The research tests the hypothesis that photorespiration is not a wasteful process, but one that generates reductant to support the conversion of nitrate and sulfate into amino acids. Therefore, C3 carbon fixation may be much more energy efficient than previously assumed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在这个由化学系生命过程化学项目资助的项目中，凯尔M。康奈尔大学的兰开斯特和加州大学戴维斯分校的阿诺德·J·布鲁姆评估了不同金属结合的作用，特别是镁与锰，在光呼吸的机制和生物能量学中的作用，其中Rubisco是地球上最普遍的蛋白质，与氧气而不是二氧化碳反应。生物无机光谱学家和植物生理学家之间的这种合作旨在为光合作用的演变以及过去，现在和未来环境条件下植物碳和氮平衡之间的关系提供新的视角。这些信息对于在未来几十年保持粮食质量和确保世界粮食安全至关重要。教授兰开斯特和布鲁姆通过地球在线百科全书的文章传播这一信息，在科学会议上的研讨会，包括一些由科学家协会组织的科学家谁是在STEM职业中代表性不足的群体的成员，并通过编写和保持最新的印刷和在线教科书使用的学生以及美国和外国专业人士的工作与环境变化有关。 拟议的研究涉及广泛的光谱，动力学和计算技术的应用，以对比蛋白质结构和植物代谢时，锰或镁结合到催化光呼吸途径中的前三个化学步骤的酶。Mn 2+结合形式的Rubisco，苹果酸酶，磷酸乙醇酸磷酸酶的特征在于通过X-射线晶体学和电子自旋共振，X-射线吸收，和磁性圆二色谱。研究了分离的完整叶绿体以及纯化的光呼吸酶。离体叶绿体的工作涉及镁和锰浓度的比率染料测量，O2和CO2消耗的光电管测量，以及光呼吸产物的质谱评估。对分离的酶进行的工作涉及核酮糖-1，5-二磷酸氧化过程中锰Rubisco的电子转移动力学的测量以及潜在的生理相关的电子转移合作伙伴的调查。 这项研究验证了这样一个假设，即光呼吸不是一个浪费的过程，而是一个产生还原剂以支持硝酸盐和硫酸盐转化为氨基酸的过程。因此，C3固碳可能比以前假设的更节能。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。