Dynamic Changes in Protein-Membrane Association for Regulating Photosynthetic Electron Transport

Abstract

Photosynthesis has to work efficiently in contrasting environments such as in shade and full sun. Rapid changes in light intensity and over-reduction of the photosynthetic electron transport chain cause production of reactive oxygen species, which can potentially damage the photosynthetic apparatus. Thus, to avoid such damage, photosynthetic electron transport is regulated on many levels, including light absorption in antenna, electron transfer reactions in the reaction centers, and consumption of ATP and NADPH in different metabolic pathways. Many regulatory mechanisms involve the movement of protein-pigment complexes within the thylakoid membrane. Furthermore, a certain number of chloroplast proteins exist in different oligomerization states, which temporally associate to the thylakoid membrane and modulate their activity. This review starts by giving a short overview of the lipid composition of the chloroplast membranes, followed by describing supercomplex formation in cyclic electron flow. Protein movements involved in the various mechanisms of non-photochemical quenching, including thermal dissipation, state transitions and the photosystem II damage–repair cycle are detailed. We highlight the importance of changes in the oligomerization state of VIPP and of the plastid terminal oxidase PTOX and discuss the factors that may be responsible for these changes. Photosynthesis-related protein movements and organization states of certain proteins all play a role in acclimation of the photosynthetic organism to the environment.

Here comes the sun: How optimization of photosynthetic light reactions can boost crop yields

“…NPQ measured by fluorescence quenching analysis is a collective term that includes several different components for the avoidance responses of photodamage. These actually do not dissipate excess energy as heat but aim at decreasing light absorption and optimizing electron distribution, such as chloroplast photorelocation, redistribution of LHCII between the photosystems (state transitions) and photoinhibitory break‐down of D1 in PSII (for a comprehensive overview and depiction see Malnoë, 2018; Messant et al, 2021). Energy dissipation in the LHCs via NPQ consists of different components with contrasting response times.…”

Modulations in Chlorophyll a Fluorescence Based on Intensity and Spectral Variations of Light

“…It has been proven that, under high light intensity, a very high oxidizing potential exists inside PSII reaction centres, which damages the key D1 core proteins. D1 protein turnover is an important part of photosynthesis recovery from stress damage, but the rate of D1 protein degradation is higher than that of its synthesis as stress intensifies; hence, PSII reaction centres will become photo-inactivated [ 38 ]. According to Faseela and Puthur, high light intensity causes a reduction in photochemical efficiency, followed by a high emission of dissipated energy in the form of fluorescence or heat, leading to damage of PSI and PSII.…”

Metamitron, a Photosynthetic Electron Transport Chain Inhibitor, Modulates the Photoprotective Mechanism of Apple Trees

“…In the current study, there is a smear behavior seen in the gel of Psb-O when the inhibitor reaches above 0.04%, corroborating the damage by ROS in this cultivar. The accumulation of ROS at the vicinity of PSII encourages the LHCII to transfer to PSI in order to minimize energy flowing towards PSII (Figure 4B); this should decrease the accumulation of ROS [9]. In turn, the accumulation of ROS in the vicinity of PSII in the TR affects the response of this cultivar to increased light intensities on the background of the inhibitor.…”

“…These processes are termed Non Photochemical Quenching (NPQ) [9], and are activated in response to the duration of the stress. Essentially, there are three major processes within NPQ that are activated at different time scales: a.…”