Site-directed mutagenesis of amino acid residues of D1 protein interacting with phosphatidylglycerol affects the function of plastoquinone QB in photosystem II

Kaichiro Endo, Naoki Mizusawa, Jian Ren Shen, Masato Yamada, Tatsuya Tomo, Hirohisa Komatsu, Masami Kobayashi, Koichi Kobayashi, Hajime Wada

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Recent X-ray crystallographic analysis of photosystem (PS) II at 1.9-Å resolution identified 20 lipid molecules in the complex, five of which are phosphatidylglycerol (PG). In this study, we mutagenized amino acid residues S232 and N234 of D1, which interact with two of the PG molecules (PG664 and PG694), by site-directed mutagenesis in Synechocystis sp. PCC 6803 to investigate the role of the interaction in PSII. The serine and asparagine residues at positions 232 and 234 from the N-terminus were mutagenized to alanine and aspartic acid, respectively, and a mutant carrying both amino acid substitutions was also produced. Although the obtained mutants, S232A, N234D, and S232AN234D, exhibited normal growth, they showed decreased photosynthetic activities and slower electron transport from QA to QB than the control strain. Thermoluminescence analysis suggested that this slower electron transfer in the mutants was caused by more negative redox potential of QB, but not in those of QA and S2. In addition, the levels of extrinsic proteins, PsbV and PsbU, were decreased in PSII monomer purified from the S232AN234D mutant, while that of Psb28 was increased. In the S232AN234D mutant, the content of PG in PSII was slightly decreased, whereas that of monogalactosyldiacylglycerol was increased compared with the control strain. These results suggest that the interactions of S232 and N234 with PG664 and PG694 are important to maintain the function of QB and to stabilize the binding of extrinsic proteins to PSII.

Original languageEnglish
Pages (from-to)385-397
Number of pages13
JournalPhotosynthesis research
Volume126
Issue number2-3
DOIs
Publication statusPublished - Dec 1 2015

Keywords

  • D1
  • Phosphatidylglycerol
  • Photosystem II
  • Site-directed mutagenesis
  • Synechocystis sp. PCC 6803

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology

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