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Degradation of D2 protein due to UV‐B irradiation of the reaction centre of photosystem II
Author(s) -
Friso G.,
Barbato R.,
Giacometti G.M.,
Barber J.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)80419-2
Subject(s) - chemistry , cleavage (geology) , photosystem ii , quinone , transmembrane domain , photochemistry , photosynthetic reaction centre , electron acceptor , transmembrane protein , stereochemistry , biochemistry , membrane , electron transfer , photosynthesis , biology , paleontology , receptor , fracture (geology)
Exposure of isolated reaction centres of photosystem II to UV‐B radiation generates specific breakdown products of the D2 protein. When the quinone, 2,5‐dibromo‐3‐methyl‐6‐isopropyl‐ p ‐benzoquinone is present a 22 kDa fragment containing the N‐terminus of the mature protein is generated. Concomitant with the appearance of the N‐terminal fragment, two fragments containing the C‐terminus of the D2 protein having apparent molecular masses around 10–12 kDa are observed. It is concluded that the primary cleavage occurs in the hydrophilic loop linking putative transmembrane segments IV and V. No such cleavage was observed when silicomolybdate was used as an electron acceptor, suggesting that this UV‐B damage is dependent on binding of the added quinone to the Q A site.