报告题目：Computational Studies of Electron Transfer in Multi-Heme Proteins
报告人：姜修允博士, Department of Physic and Astronomy, University College London
Bacteria like Shewanella and Geobacter are species that express multi-heme proteins which enable them to respire and survive without oxygen by reduction of extracellular solid substrates. Multi-heme proteins are fascinating biomolecules that bind several redox-active heme cofactors in close distance. They have attracted much attention recently due to their prominent role in mediating extracellular electron transport. Based on Marcus theory and the electron hopping model (i.e., electron transport through the protein occurs via sequential electron hopping along the heme chains), I have used density functional theory (DFT) and molecular dynamics (MD) simulation to calculate all heme-to-heme electron transfer (ET) rate constants in three ubiquitous multi-heme proteins binding 4 and 10 heme cofactors. My calculations revealed that electron hopping through these proteins is strongly enhanced by cysteines that insert in the space between heme groups. We believe this to be a general design principle in multi-heme proteins for acceleration of ET steps that would otherwise be too slow for biological respiration. In the second part of my presentation, I will talk about a collaborated work to verify our computed rate constants. To this end, our experimental collaborators docked a Ru-chromophore close to a terminal heme of one of the multi-heme proteins studied and used ultrafast pump-probe spectroscopy to monitor electron injection in the protein and subsequent relaxation dynamics. From these measurements we could extract a heme-heme ET rate that is in good agreement with our predicted result.
姜修允于2015毕业于复旦大学物理系自然科学实验班，之后到University College London (UCL), London, United Kingdom读博士，毕业后在该校做博士后，并加入Computational Studies of Electron Transfer in Multi-Heme Proteins和导师: Prof. Dr. Jochen Blumberger从事多血红素蛋白质内电子转移的计算研究。课题旨在研究多血红素蛋白质内电子长程输运的机制，并用Marcus理论预测血红素-血红素电子转移反应的反应速率。运用classical force field, polarizable force field, hybrid QM/MM等方法来研究如何准确计算化学反应重组自由能这一参数。模拟多血红素蛋白质分子STC的超快激光的实验信号，对比模拟计算的反应速率结果，证明了理论模拟结果的合理性。姜修允博士后在J. Phys. Chem. B，J. Am. Chem. Soc，Proc. Nat. Acad. Sci. USA，Chem. Sci.，Physics Experimentation等期刊上发表了相关的文章。