Collaborative Research: Understanding Electron Bifurcation in Methanogenic Archaea

有了这个奖项，生命过程化学计划正在资助奥本大学的Evert Duin博士和华盛顿大学的John Leigh博士研究电子分叉的重要过程，这是生命系统将能量从一种形式转化为另一种形式时发生的。在这个过程中，两个电子以相同的电势进入系统，但当它们离开时，其中一个的电势比另一个低得多。 因此，电子分叉使得生物分子的上坡的、需要能量的电子还原成为可能，因为下坡的氧化伴随发生，这平衡了能量消耗和产生。 这一过程在产生生物燃料的生物体的甲烷产生和消耗功能中被观察到，但也在其他形式的生命中被观察到，包括我们自己的身体。了解这一过程的工作原理可能有助于改善沼气的生产或帮助优化甲烷向生物柴油的转化，并可以帮助我们回答各种与健康相关的问题。 这项研究对培养各级学生成为下一代科学家产生了更广泛的影响。 该项目的合作性质涉及来自美国不同地理区域的团体，为学生获得跨学科和合作研究的技能创造了一个环境。电子分叉使酶能够通过同时产生具有高氧化还原电位的电子来产生具有非常低氧化还原电位的电子。这消除了将前一电子转移步骤与ATP水解偶联的需要。分叉过程总是涉及醌或黄素基团。Duin和Leigh小组将研究氢化酶：杂二硫还原酶复合物的电子分叉，该复合物在铁硫簇中含有铁离子。 该理论认为，一些铁硫簇在电子分叉过程中发挥了重要作用，它们向中心黄素提供电子，然后接受高或低电势的电子。将使用定点诱变来改变铁-硫簇和黄素及其直接包被。 这些变化的电子和磁性的集群和黄素的后果将通过吸收，电子顺磁共振，和磁性圆二色性光谱和分叉过程将通过确定的氧化还原特性的集群和黄素和氧化还原过程的动力学检查评估。

With this award, the Chemistry of Life Processes Program is funding Dr. Evert Duin of Auburn University and Dr. John Leigh of the University of Washington to study the important process of electron bifurcation, which occurs when living systems convert energy from one form to another. In this process, two electrons enter the system with identical potential, but when they exit, one has a much lower potential than the other. Consequently, electron bifurcation makes possible an uphill, energy-demanding, electron reduction of a biological molecule because a downhill oxidation occurs concomitantly, which balances the energy consumption and generation. The process has been observed in the methane-producing and -consuming functions of Archaea, which produce biofuels, but also in other forms of life, including our own bodies. Understanding how this process works could be beneficial for improving the production of biogas or helping to optimize the conversion of methane to biodiesel and could help us answer a variety of health-related questions. The research has a further broader impact on the preparation of students at all educational levels to become the next generation of scientists. The collaborative nature of the project that involves groups from different geographic regions of the United States creates an environment in which the students acquire skills for interdisciplinary and collaborative research.Electron bifurcation enables enzymes to create electrons with a very low redox potential by simultaneously creating an electron with a high redox potential. This eliminates the need to couple the former electron transfer step to ATP hydrolysis. The bifurcation process always involves a quinone or flavin group. The Duin and Leigh groups will study the electron bifurcation by the hydrogenase:heterodisulfide reductase complex, which contains iron ions within iron-sulfur clusters. The theory is that some of the iron-sulfur clusters play an important part in the electron bifurcation process by donating electrons to the central flavin and then accepting either the high or low potential electrons. Site-direct mutagenesis will be used to make changes to the iron-sulfur clusters and to the flavins and their direct envoironment. The consequences of these changes on the electronic and magnetic properties of the clusters and flavin will be evaluated by absorption, electron paramagnetic resonance, and magnetic circular dichroism spectroscopies and on the bifurcation process will be examined by determining the redox properties of the clusters and flavin and the kinetics of the redox processes.