Photosystem I

Light-dependent reactions of photosynthesis at the thylakoid membrane
Photosystem I
Plant photosystem I with LHC I
Identifiers
EC no.1.97.1.12
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IntEnzIntEnz view
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MetaCycmetabolic pathway
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NCBIproteins
Location of the psa genes in the chloroplast genome of Arabidopsis thaliana. The 21 protein-coding genes involved in photosynthesis are displayed as green boxes.

Photosystem I (PSI, or plastocyanin–ferredoxin oxidoreductase) is one of two photosystems in the photosynthetic light reactions of algae, plants, and cyanobacteria. Photosystem I [1] is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. Ultimately, the electrons that are transferred by Photosystem I are used to produce the moderate-energy hydrogen carrier NADPH.[2] The photon energy absorbed by Photosystem I also produces a proton-motive force that is used to generate ATP. PSI is composed of more than 110 cofactors, significantly more than Photosystem II.[3]

  1. ^ Golbeck JH (1987). "Structure, function and organization of the Photosystem I reaction center complex". Biochimica et Biophysica Acta (BBA) - Reviews on Bioenergetics. 895 (3): 167–204. doi:10.1016/s0304-4173(87)80002-2. PMID 3333014.
  2. ^ Yamori W, Shikanai T (April 2016). "Physiological Functions of Cyclic Electron Transport Around Photosystem I in Sustaining Photosynthesis and Plant Growth". Annual Review of Plant Biology. 67: 81–106. doi:10.1146/annurev-arplant-043015-112002. PMID 26927905.
  3. ^ Nelson N, Yocum CF (2006). "Structure and function of photosystems I and II". Annual Review of Plant Biology. 57: 521–65. doi:10.1146/annurev.arplant.57.032905.105350. PMID 16669773.