2pm - 3pm
Thursday 22 July 2021
Energy transfer mechanisms in light-harvesting complexes of Rhodobacter sphaeroides / Magnetoreception and the radical pair mechanism
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Energy transfer mechanisms in light-harvesting complexes of Rhodobacter sphaeroides
During the light dependent reactions of photosynthesis of purple bacteria, light harvesting (LH) complexes absorb and direct energy towards a reaction centre with an efficiency of approximately 95% . One of the hypotheses explaining this phenomenon argues that such high efficiency is achieved thanks to a quantum coherent state occurring between the bacteriochlorophyll molecules enclosed within these proteins. In the present study we will genetically modify the scaffold of LHs expressed by Rhodobacter sphaeroides for tuning the interactions occurring between their pigment molecules. A series of time-resolved spectroscopic analysis will be then carried for a set of the variants obtained. The data collected throughout this project will constitute a foundation for experiments aiming at understanding whether quantum coherence plays a non-trivial role in photosynthesis. Moreover, it represents the first step in the development of high-performance technologies for sunlight harvesting.
 Fleming, G. R., van Grondelle, R. (1997). Femtosecond spectroscopy of photosynthetic light-harvesting systems. Current opinion in structural biology, 7(5), 738-748.
Eve completed her bachelor’s degree in Biological Sciences in 2015 from The Rural Federal University of Rio de Janeiro (Brazil) and just after received a full scholarship to pursue her Master’s degree in Marine Environment and Resources in Europe through the Erasmus Mundus Programme. As a microbiologist with great interest in biophysics, she was fascinated by the possibility of living organisms to explore quantum effects when she heard about it for the first time in 2018. In this way, she didn’t think twice before applying for a position at the Quantum Biology Doctoral Training Centre at the University of Surrey, where now, she investigates whether and how quantum mechanics can play an important whole in microbial photosynthesis.
Magnetoreception and the radical pair mechanism
Magnetoreception is the phenomenon by which some birds and other animals make seasonal migrations using the Earth’s magnetic field (MF) for directional information. But how can the Earth, with magnetic fields ~ 500 times smaller than your average refrigerator magnet, be effecting change on the robust nature of biology? Since the early 2000’s the ‘radical pair mechanism’ has been the forerunning theory to explain how animals, plants and insects are able to ‘see’ magnetic field lines. As prevalent as radicals are throughout biology, however, there are very few systems with conditions sufficient to give rise to even a potential radical pair mechanism. Whether the biological system has evolved to harness it is yet another layer to the proverbial onion. In my talk I will briefly take you through the history of research into animal magnetoreception, the radical pair mechanism and the constraints on such a system.
Edeline completed her Bachelor’s of Science in Biomedical Science at the University of Surrey. During this program she did her professional training year at Texas A&M University in the Threadgill lab, on the role of diet and the microbiome in varying genetic backgrounds of inbred mouse models of carcinogenesis. In addition to her professional inclinations towards the biological, her long fascination with physics and all things quantum culminated, fortuitously, in a PhD at the Quantum Biology DTC at the University of Surrey. Her research delves into the investigation and bioengineering of the photoreceptor, cryptochrome, and its potential role in light-dependent magnetosensing.