InterPro domain: IPR037497

PGR5 is involved in the regulation of the cyclic electron flow around Photosystem I [ 1 ]. Two types of electron transfer contribute to the proton concentration gradient across the thylakoid membrane: linear electron flow (LEF) and cyclic electron flow (CEF), which is divided into NDH- and PGR5-dependent pathways. The PGR5-PGRL1 complex mediates the second CET circuit, accepting electrons from ferrodoxin and reducing the plastoquinone pool. PGR5 is important to regulate and facilitate CET, and is essential for photoprotection in Arabidopsis [ 2 , 3 , 4 ].

1. Relative contributions of PGR5- and NDH-dependent photosystem I cyclic electron flow in the generation of a proton gradient in Arabidopsis chloroplasts. Planta 11, e1165382
2. PGR5 is involved in cyclic electron flow around photosystem I and is essential for photoprotection in Arabidopsis. Cell 228, 907-18
3. Conserved role of proton gradient regulation 5 in the regulation of PSI cyclic electron transport. Planta 24, 2934-48
4. PROTON GRADIENT REGULATION5 is essential for proper acclimation of Arabidopsis photosystem I to naturally and artificially fluctuating light conditions. Plant Cell