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Identification of the phosphorylation site of an 8.3 kDa protein from photosystem II of spinach
Author(s) -
Michel H.P.,
Bennett J.
Publication year - 1987
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(87)81565-x
Subject(s) - phosphopeptide , biochemistry , photosystem ii , phosphorylation , chemistry , chloroplast , spinach , peptide , affinity chromatography , protein phosphorylation , peptide sequence , residue (chemistry) , proteolysis , protein kinase a , enzyme , photosynthesis , gene
The four principal phosphoproteins of PS II cores (8.3, 32, 34 and 44 kDa) give rise to distinct tryptic phosphopeptides which have been purified by affinity chromatography on Fe 3+ ‐chelating Sepharose and reverse‐phase HPLC. The tryptic phosphopeptide derived from the 8.3 kDa protein has the sequence NH 2 ‐Ala‐Thr‐Gln‐Thr‐Val‐Glu‐Ser‐Ser‐Ser‐Arg. It corresponds to the N‐terminus of the chloroplast psbH gene product, except for the loss of the initiating N ‐formylmethionine. The peptide is phosphorylated on the first threonyl residue. Differences between the phosphorylation sites of the 8.3 kDa protein and LHC II are consistent with the hypothesis that thylakoids contain two distinct redox‐controlled protein kinases differing in substrate specificity.