Using EPR spectroscopy to probe electron transfer in biology: from model molecular wires to complex metalloenzymes

作为脉冲电子顺磁共振波谱中心(PEPR)的一部分，罗斯勒研究小组提供了一个全额资助的博士职位。PEPR是伦敦帝国理工学院的一个主要新设施，最近在怀特城校区启动。Roessler团队研究了氧化还原反应中的未配对电子，这些反应支撑了呼吸作用和光合作用中的基本化学反应。我们应用脉冲EPR技术[1]来理解挑战酶的机制，这些酶在高浓度下无法获得，需要精确的电化学电位调整[2，3]。我们还在开发膜电化学EPR光谱(FE-EPR)，这是一种研究反应过程中自由基演化的令人兴奋的技术[4]。Fe EPR可以准确地测定埋藏在酶中的氧化还原中心的氧化还原电位及其在催化过程中的活性。PEPR将X和Q波段的脉冲EPR与FE-EPR相结合，并与伦敦大学学院和伦敦纳米技术中心合作开发仪器[5]。在这个项目中，您将应用PEPR提供的最先进的仪器，以及FE-EPR的独特功能，以我们最近关于光合作用复合体I[2]内的电子转移和呼吸复合体中的能量耦合[3]的发现为基础。您将对如何最好地利用PULSE EPR的最新进展，使用模型分子线研究复杂的顺磁中心有一个基本的了解。在此基础上，我们将研究复杂的I型酶如何利用电子转移来泵送对ATP合成至关重要的质子。该项目是跨学科和协作的，根据您为项目选择的重点，您将有机会将物理/物理化学(高级EPR，电化学)、材料科学(用于电极的制造和表征)、生化方法(制造和操纵膜蛋白)和化学合成(制造模型分子线)结合在一起。你应该对物理化学或生物化学有浓厚的兴趣和背景。[1]M.Roessler和E.Saladori，《化学学会评论》，2018年，47(8)，2534-2553[2]K.H.Richardson，J.J.Wright，M.Simenas，J.Thiemann，A.M.Esteves，G.McGuire，W.K.Myers，J.J.L.Morton，M.Hippler，M.M.Nowaczyk，G.T.Hanke，M.M.Roessler，《光合作用复合体中电子传递的功能基础》，《自然通讯》，2021，12,5387，新闻稿[3]N.le Breton，J.J.Wright，A.J.Y.J.Jones，E.萨尔瓦多，H.R.Bridges，J.Hirst，M.Roessler，《使用EPR超精细光谱定义呼吸复合体中Fe-S团簇N_2处的质子耦合电子转移反应》，J.Am化学。2017,139(45)，16319-16326，聚焦文章[4]K.Abdiaziz，E.萨尔瓦多，K.P.Sokol，E.Reisner，M.Roessler，《蛋白质膜电化学EPR光谱作为一种研究生物分子中氧化还原反应的技术》，化学通信，2019年，55(60)，8840-8843[5]M Simenas，J O‘Sullivan，CW Zollitsch，O Kennedy，M Seif-Eddine，I Ritsch，M Jessmann，M，A Godt，MM Roessler，G，JL Morton，[5]M Simenas，J O’Sullivan，CW Zollitsch，O Kennedy，M Seif-Eddine，I Ritsch，M Jessmann，M，A Godt，MM Roessler，G《利用带有低温前置放大器的探针头实现X波段电子顺磁共振的灵敏度飞跃》，《磁共振杂志》2021322,106876

A fully funded PhD position is available in the Roessler research group as part of the Centre for Pulse EPR spectroscopy (PEPR). PEPR is a major new facility at Imperial College London and was recently launched at the White City Campus. The Roessler group investigates unpaired electrons in redox reactions that underpin essential chemical reactions in respiration and photosynthesis. We apply pulse EPR techniques [1] to understand the mechanisms of challenging enzymes that cannot be obtained in high concentrations and require precise electrochemical potential adjustment [2,3]. We are also developing film-electrochemical EPR spectroscopy (FE-EPR), an exciting technique for studying the evolution of radicals during a reaction [4]. FE EPR allows the accurate determination of the redox potentials of buried redox centres within enzymes and their activity during catalysis. PEPR combines pulse EPR at X- and Q-band frequencies with FE-EPR and instrument development in collaboration with University College London and the London Centre of Nanotechnology [5].In this project, you will apply the state-of-art instrumentation available at PEPR, together with the unique capabilities of FE-EPR, to build on our recent findings of electron transfer within photosynthetic complex I [2] and energy-coupling in respiratory complex [3]. You will acquire a fundamental understanding of how best to harness the recent advances in pulse EPR to investigate complex paramagnetic centres using model molecular wires. Using this foundation, we will study how complex I type enzymes use electron transfer to pump protons that are essential for ATP synthesis. The project is interdisciplinary and collaborative, and depending on your choice of focus for your project you will have the opportunity to combine physics/physical chemistry (advanced EPR, electrochemistry), material science (for the fabrication and characterisation of electrodes), biochemical methods (making and manipulating membrane proteins) and chemical synthesis (making model molecular wires). You should have a keen interest and background in physical chemistry or biochemistry. Previous exposure to EPR spectroscopy is an asset but not an essential requirement.[1] M. M. Roessler and E. Salvadori, 'Principles and Applications of EPR Spectroscopy in the chemical sciences', Chemical Society Reviews, 2018, 47 (8), 2534-2553[2] K.H. Richardson, J.J. Wright, M. Simenas, J. Thiemann, A.M. Esteves, G. McGuire, W.K. Myers, J.J.L. Morton, M. Hippler, M.M. Nowaczyk, G.T. Hanke, M.M. Roessler, 'Functional basis of electron transport within photosynthetic complex I', Nature Communications, 2021, 12, 5387, Press Release[3] N. le Breton, J. J. Wright, A.J.Y.J. Jones, E. Salvadori, H. R. Bridges, J. Hirst, M. M. Roessler, 'Using EPR Hyperfine Spectroscopy to define the Proton-Coupled Electron Transfer Reaction at Fe-S cluster N2 in Respiratory Complex I', J. Am. Chem. Soc., 2017, 139 (45), 16319-16326, Spotlight Article[4] K. Abdiaziz, E. Salvadori, K.P. Sokol, E. Reisner, M.M. Roessler, 'Protein film electrochemical EPR spectroscopy as a technique to investigate redox reactions in biomolecules', Chemical Communications, 2019, 55 (60), 8840-8843[5] M Simenas, J O'Sullivan, CW Zollitsch, O Kennedy, M Seif-Eddine, I Ritsch, M Hulsmann, M Qi, A Godt, MM Roessler, G Jeschke, JJL Morton, 'A sensitivity leap for X-band EPR using a probehead with a cryogenic preamplifier', Journal of Magnetic Resonance 2021 322, 106876