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ID 46923
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Author
Kawakami, Keisuke
Umena, Yasufumi
Iwai, Masako
Kawabata, Yousuke
Ikeuchi, Masahiko
Kamiya, Nobuo
Abstract
PsbM and PsbI are two low molecular weight subunits of photosystem II (PSII), with PsbM being located in the center, and PsbI in the periphery, of the PSII dimer. In order to study the functions of these two subunits from a structural point of view, we crystallized and analyzed the crystal structure of PSII dimers from two mutants lacking either PsbM or PsbI. Our results confirmed the location of these two subunits in the current crystal structure, as well as their absence in the respective mutants. The relative contents of PSII dimers were found to be decreased in both mutants, with a concomitant increase in the amount of PSII monomers, suggesting a destabilization of PSII dimers in both of the mutants. On the other hand, the accumulation level of the overall PSII complexes in the two mutants was similar to that in the wild-type strain. Treatment of purified PSII dimers with lauryldimethylamine N-oxide at an elevated temperature preferentially disintegrated the dimers from the PsbM deletion mutant into monomers and CP43-less monomers, whereas no significant degradation of the dimers was observed from the PsbI deletion mutant. These results indicate that although both PsbM and PsbI are required for the efficient formation and stability of PSII dimers in vivo, they have different roles, namely, PsbM is required directly for the formation of dimers and its absence led to the instability of the dimers accumulated. On the other hand, PsbI is required in the assembly process of PSII dimers in vivo; once the dimers are formed, PsbI was no longer required for its stability.
Keywords
Photosystem II
Mutant
Crystal structure
PsbM
PsbI
Oxygen evolution
Published Date
2011-03
Publication Title
Biochimica et Biophysica Acta (BBA) - Bioenergetics
Volume
volume1807
Issue
issue3
Publisher
Elsevier Science BV.
Start Page
319
End Page
325
ISSN
0005-2728
NCID
AA00564646
Content Type
Journal Article
Project
Research Center of New Functional Materials for Energy Production, Storage, and Transport
language
英語
Copyright Holders
© 2010 Elsevier B.V. All rights reserved.
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True
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