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Updated: Jul 11, 2026

In Vitro Reconstitution of Light-harvesting Complexes of Plants and Green Algae
Published on: October 10, 2014
Location of PsbY in oxygen-evolving photosystem II revealed by mutagenesis and X-ray crystallography
Keisuke Kawakami1, Masako Iwai, Masahiko Ikeuchi
1Division of Bioscience, Graduate School of Natural Science and Technology/Faculty of Science, Okayama University, Okayama 700-8530, Japan.
Abstract:
PsbY is one of the low molecular mass subunits of oxygen-evolving photosystem II (PSII). Its location, however, has not been identified in the current crystal structure of PSII. We constructed a PsbY-deletion mutant of Thermosynechococcus elongatus, crystallized, and analyzed the crystal structure of the mutant PSII dimer. The results obtained showed that PsbY is located in the periphery of PSII close to the alpha- and beta-subunits of cytochrome b559, which corresponded to an unassigned helix in the 3.7A structure of T. vulcanus or helix X2 in the 3.0A structure of T. elongatus. Our results also indicated that the C-terminal loop of PsbY is protruded toward the stromal side, instead of the lumenal side predicted previously.
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