Differentiating the Two Complementary Flavins in a Bifurcating Electron Transfer Flavoprotein

区分二叉电子转移黄素蛋白中的两种互补黄素

• 批准号: 2108134
• 负责人: Anne-Frances Miller
• 金额: $ 45.89万
• 依托单位: University of Kentucky Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108134&HistoricalAwards=false
• 关键词: Differentiating; Two; Complementary; Flavins; Bifurcating

With support from the Chemistry of Life Processes Program in the Division of Chemistry, Professor Anne-Frances Miller and her team at the University of Kentucky are examining how bacteria have managed to optimize their energy efficiency. Science has advanced to the point that it is now possible to supply all the energy needed by mankind, from wind and sunlight. However, these are intermittent, low-density sources that need to be 'stepped up' to power appliances such as hair driers. It turns out that bacteria possess enzymes capable of producing concentrated power from readily available fuel sources. These enzymes employ a mechanism wherein pairs of electrons are obtained from a cheap abundant fuel, but only one of the electrons is allowed to run 'down-hill'. The enzyme somehow harnesses this favorable process to drive an unfavorable 'up-hill' reaction that yields a much more potent electron carrier than the starting one. To enable design of materials able to do the same, the proposed research seeks to learn how nature does this. Flavin molecules related to the vitamin riboflavin, bound in proteins as cofactors are central to the mechanism. The planned research seeks to elucidate how the protein adjusts the flavin's reactivity. Flavins are yellow and fall into the larger chemical category of pigments. The broader impact of this work will be to develop a course for non-chemists that will employ fiber art and dyeing activities to explain core chemical concepts. This hands-on learning approach is designed to reach audiences who do not find book- and lecture-based courses compelling. Thus, the proposed work aims to engage a larger audience in the fun and curiosity of chemistry, and to harness chemistry in larger service to society.This research seeks to learn how bifurcating electron transfer flavoproteins (ETFs) tune the reactivities of their two flavins to cause one flavin to execute single electron transfers only, but the other flavin to have a very high energy semiquinone state that causes transfer of one electron to be tightly coupled to transfer of the second. A specific hypothesis is that the pyrophosphate group built into flavin adenine dinucleotide (FAD) could have agency in modulating the activity of the flavin. The proposed work also addresses the nature and lessons inherent in a novel state of the ETF that is proposed to involve cooperation of both flavins. The research integrates computational, spectroscopic, electrochemical, and biochemical strategies. To develop computational approaches and enable interpretation of flavin optical spectra in terms of underlying electronic structure and reactivity, a systematic approach is proposed, beginning with covalently modified flavins. Once validated, computational approaches would then be employed to infer the electronic perturbations produced by different protein sites in which flavins are bound. While flavin spectroscopy is at the center of the proposed research, the proposal exploits pigments more generally as vehicles to make core concepts of chemistry accessible to non-scientist audiences. A lab and lecture course on plant pigments in fiber arts will be developed into a modular on-line course, including guidance for hands-on activities. The team will assemble execution kits that rural schools or homeschoolers will be able to borrow, in order to follow along with recorded demonstrations and presentations. This approach seeks to overcome barriers that prevent many people from engaging with chemistry.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.

在化学系生命过程化学项目的支持下，肯塔基州大学的Anne-Frances米勒教授和她的团队正在研究细菌如何设法优化其能源效率。 科学已经发展到这样一个地步，现在有可能从风能和太阳能中提供人类所需的所有能源。然而，这些都是间歇性的，低密度的来源，需要“加强”电源设备，如吹风机。事实证明，细菌拥有能够从容易获得的燃料源中产生浓缩动力的酶。这些酶采用一种机制，其中电子对是从廉价的丰富燃料中获得的，但只有一个电子被允许“下山”。酶以某种方式利用这个有利的过程来驱动一个不利的“上山”反应，产生一个比起始的电子载体更有效的电子载体。为了使材料的设计能够做到这一点，拟议的研究旨在了解自然界是如何做到这一点的。与维生素核黄素相关的黄素分子，作为辅因子结合在蛋白质中，是该机制的核心。计划中的研究试图阐明蛋白质如何调节黄素的反应性。黄素是黄色的，属于色素的较大化学类别。这项工作的更广泛的影响将是为非化学家开发一门课程，该课程将采用纤维艺术和染色活动来解释核心化学概念。这种动手学习的方法是为了达到观众谁不觉得书和讲座为基础的课程引人注目。因此，这项工作的目的是让更多的观众参与到化学的乐趣和好奇心中，并利用化学为社会服务。这项研究旨在了解分叉电子转移黄素蛋白（ETFs）如何调节它们两个黄素的反应性，使一个黄素只执行单电子转移，但另一种黄素具有非常高的能量半醌状态，其导致一个电子的转移与第二个电子的转移紧密耦合。一个具体的假设是，黄素腺嘌呤二核苷酸（FAD）中的焦磷酸基团可能具有调节黄素活性的作用。拟议的工作还解决了本质和经验教训固有的一种新的状态的ETF，提出涉及合作的两个黄素。该研究整合了计算，光谱，电化学和生物化学策略。为了开发计算方法，并使解释黄素的光学光谱的基础电子结构和反应性，提出了一个系统的方法，从共价修饰的黄素。一旦验证，计算方法将被用来推断电子扰动所产生的不同蛋白质的网站，其中结合黄素。虽然黄素光谱是拟议研究的中心，但该提案更广泛地利用色素作为载体，使非科学家受众能够理解化学的核心概念。纤维艺术中植物颜料的实验室和讲座课程将发展成一个模块化的在线课程，包括实践活动的指导。 该小组将组装执行工具包，农村学校或在家上学的人将能够借用，以便沿着记录演示和演示。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。