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Photoaffinity labeling of the phylloquinone‐binding polypeptides by 2‐azidoanthraquinone in photosystem I particles
Author(s) -
Iwaki Masayo,
Takahashi Masaaki,
Shimada Keizo,
Takahashi Yuichiro,
Itoh Shigeru
Publication year - 1992
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(92)81403-9
Subject(s) - photoaffinity labeling , chemistry , anthraquinone , photosystem ii , spinach , photosystem i , photosynthetic reaction centre , quinone , affinity labeling , affinity label , gel electrophoresis , polyacrylamide gel electrophoresis , photosystem , photochemistry , binding site , biochemistry , electron transfer , photosynthesis , organic chemistry , enzyme
A photoaffinity label, 2‐azido‐9,10‐anthraquinone, binds at the quinone‐binding (Q φ ) site with high affinity and can substitute for the secondary acceptor, phylloquinone, in photosystem I reaction center of spinach. Phylloquinone‐depleted photosystem I particles reconstituted with azido‐[ 3 H]anthraquinone were illuminated with UV light and analyzed by sodium dodecylsulfate‐polyacrylamide gel electrophoresis. The large core polypeptides ( psaA and/or psaB ) were selectively labeled. The labeling was competitively inhibited in the presence of anthraquinone. These results indicate that the Q φ site is located on psaA or psaB polypeptides.