Role of phosphatidylglycerol in the function and assembly of Photosystem II reaction center, studied in a cdsA-inactivated PAL mutant strain of Synechocystis sp. PCC6803 that lacks phycobilisomes

Hajnalka Laczkó-Dobos, Bettina Ughy, Szilvia Z. Tóth, Josef Komenda, Ottó Zsiros, Ildikó Domonkos, Árpád Párducz, Balázs Bogos, Masayuki Komura, Shigeru Itoh, Zoltán Gombos

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30 Citations (Scopus)

Abstract

To analyze the role of phosphatidylglycerol (PG) in photosynthetic membranes of cyanobacteria we used two mutants of Synechocystis sp. PCC6803: the PAL mutant which has no phycobilisomes and shows a high PSII/PSI ratio, and a mutant derived from it by inactivating its cdsA gene encoding cytidine 5'-diphosphate diacylglycerol synthase, a key enzyme in PG synthesis. In a medium supplemented with PG the PAL/ΔcdsA mutant cells grew photoautotrophically. Depletion of PG in the medium resulted (a) in an arrest of cell growth and division, (b) in a slowdown of electron transfer from the acceptor QA to QB in PSII and (c) in a modification of chlorophyll fluorescence curve. The depletion of PG affected neither the redox levels of QA nor the S2 state of the oxygen-evolving manganese complex, as indicated by thermoluminescence studies. Two-dimensional PAGE showed that in the absence of PG (a) the PSII dimer was decomposed into monomers, and (b) the CP43 protein was detached from a major part of the PSII core complex. [35S]-methionine labeling confirmed that PG depletion did not block de novo synthesis of the PSII proteins. We conclude that PG is required for the binding of CP43 within the PSII core complex.

Original languageEnglish
Pages (from-to)1184-1194
Number of pages11
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1777
Issue number9
DOIs
Publication statusPublished - Sep 1 2008

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Keywords

  • Cell division
  • OJIP transient
  • Phosphatidylglycerol
  • Photosystem II
  • Synechocystis sp. PCC6803
  • Thermoluminescence

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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