March 22, 2022
Understanding the Mechanism of Photoprotection in Photosynthetic Organisms
Non-photochemcial quenching (NPQ) plays an important role in photoprotection in photosynthetic organisms. In collaboration with the Fleming group, we have studied the photoprotection dynamics of Nannochloropsis oceanica. A complex NPQ response is observed in experiments that mimic natural light conditions. These observations are rationalized with a quantitative model based on the xanthophyll cycle and the protonation of LHCX1. The combined model and observations suggest that the accumulation of a quenching complex, likely zeaxanthin bound to a protonated LHCX1, is responsible for the observed NPQ kinetics. Our model gives insight into the key steps in photoprotection in Nanno, and provides a platform for understanding more photoprotection mechanisms in more complex photosynthetic organisms.Tomas Fray is postdoctoral researcher in theoretical chemistry, working in the Limmer group. He obtained his DPhil in Physical and Theoretical Chemistry from the University of Oxford, in David Manolopoulos's research group, having worked on a range of problems in spin chemical systems, in which non-equilibrium quantum dynamics of coupled spins control chemical reactivity. His previous research has focussed on both the fundamental theory of spin chemistry, and its applications in avian magnetoreception, artificial photosynthesis, and chirality induced spin selectivity. His current interests lie in understanding the multiscale dynamics of complex photo-excited systems, such as those found in photosynthesis.