able to release some light energy as heat, but the excess light can also produce reactive oxygen species. While some of these can be detoxified by antioxidants, the remaining oxygen species will be detrimental to the photosystems of the plant. More specifically, the D1 subunit in the reaction center of PSII can be damaged. Studies have found that deg1 proteins are involved in the degradation of these damaged D1 subunits. New D1 subunits can then replace these damaged D1 subunits in order to allow PSII to function properly again. See also Light reaction Photoinhibition Photosynthetic reaction centre References External links Photosystems I + II: Imperial College, Barber Group Photosystem I: Molecule of the Month in the Protein Data Bank Photosystem II: Molecule of the Month in the Protein Data Bank Photosystem II: ANU UMich Orientation of Proteins in Membranes – Calculated spatial positions of photosynthetic reaction centers and photosystems in membrane Photosynthesis Light reactions Metalloproteins Integral membrane proteins