Chen, M.; Sawicki, A.; Wang, F. Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism. Microorganisms2023, 11, 2305.
Chen, M.; Sawicki, A.; Wang, F. Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism. Microorganisms 2023, 11, 2305.
Chen, M.; Sawicki, A.; Wang, F. Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism. Microorganisms2023, 11, 2305.
Chen, M.; Sawicki, A.; Wang, F. Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism. Microorganisms 2023, 11, 2305.
Abstract
Photosystem II (PSII) is a quinone-utilising photosynthetic system that converts light energy into chemical energy and catalyses the splitting of water. PsbA (D1) and PsbD (D2) are the core subunits of the reaction centre that provide most of the ligands to the redox-active cofactors and exhibit photooxidoreductase activities that convert quinone and water into quinol and oxygen. This analysis explored the putative uncoupled electron transfer pathways surrounding P680+ induced by far-red light (FRL) based on photosystem II (PSII) complexes containing substituted D1 subunits in Halomicronema hongdechloris. Chlorophyll f-synthase (ChlF) is a D1 protein paralog. Modelling PSII-ChlF complexes determined several key protein motifs of ChlF. The PSII complexes showed a dysfunctional Mn4CaO5 cluster if ChlF replaced the D1 protein. We propose the mechanism of chlorophyll f synthesis from chlorophyll a via free radical chemistry in an oxygenated environment created by over-excited pheophytin a and an inactive water splitting reaction due to an uncoupled Mn4CaO5 cluster in PSII-ChlF complexes. The role of ChlF in the formation of an inactive PSII reaction centre is under debate and the putative mechanisms of chlorophyll biosynthesis are discussed.
Biology and Life Sciences, Biochemistry and Molecular Biology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
