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

一个完全资助的博士职位是在罗斯勒研究小组作为脉冲EPR光谱中心（PEPR）的一部分。PEPR是伦敦帝国理工学院的一个主要新设施，最近在白城校区启动。Roessler小组研究了氧化还原反应中的未成对电子，这些未成对电子是呼吸和光合作用中基本化学反应的基础。我们应用脉冲EPR技术[1]来了解挑战酶的机制，这些酶不能以高浓度获得，需要精确的电化学电位调节[2，3]。我们还在开发薄膜电化学EPR光谱（FE-EPR），这是一种研究反应过程中自由基演变的令人兴奋的技术[4]。FE EPR可以准确测定酶内埋藏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波段和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]。在本项目中，您将应用PEPR提供的最先进的仪器，以及FE-EPR的独特功能，建立在我们最近发现的光合复合物I [2]和呼吸复合物[3]中的能量耦合的电子转移。您将获得如何最好地利用脉冲EPR的最新进展，使用模型分子线调查复杂的顺磁中心的基本理解。利用这个基础，我们将研究复合物I型酶如何使用电子转移来泵送ATP合成所必需的质子。该项目是跨学科和合作，并根据您的项目重点的选择，您将有机会结合联合收割机物理/物理化学（先进的EPR，电化学），材料科学（用于电极的制造和表征），生物化学方法（制造和操纵膜蛋白）和化学合成（制造模型分子线）。你应该对物理化学或生物化学有浓厚的兴趣和背景。以前接触EPR光谱是一种资产，但不是一个必要的要求。[1]M. M. Roessler和E. Salvadori，“EPR光谱在化学科学中的原理和应用”，Chemical Society Reviews，2018，47（8），2534-2553[2] K.H.作者：J. J. Simenas，J. Thiemann，A.M. Esteves，G. McGuire，W.K.迈尔斯Morton，M. Hippler，M.M. G.T.诺瓦奇克汉克，M.M. Roessler，“光合复合物I内电子传递的功能基础”，Nature Communications，2021，12，5387，新闻稿[3] N。李布雷东，J. J. Wright，A. J. Y. J. Jones，E. Salvadori，H. R. Bridges，J. Hirst，M. M. Roessler，“使用EPR超精细光谱来定义呼吸复合物I中Fe-S簇N2处的质子耦合电子转移反应”，J. Am.化学会，2017，139（45），16319-16326，Spotlight Article[4] K. Abdiaziz，E.索科尔，E. Reisner，M.M. Roessler，“蛋白质膜电化学EPR光谱作为研究生物分子中氧化还原反应的技术”，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，“使用具有低温预分解器的探头实现X波段EPR的灵敏度飞跃”，磁共振杂志2021 322，106876

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