Directed inactivation of the psbl gene does not affect Photosystem II in the cyanobacterium Synechocystis sp. PCC 6803

Masahiko Ikeuchi, Vipula K. Shukla, Himadri B. Pakrasi, Yorinao noue

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

PsbI is a small, integral membrane protein component of photosystem II (PSII), a pigment-protein complex in cyanobacteria, algae and higher plants. To understand the function of this protein, we have isolated the psbI gene from the unicellular cyanobacterium Synechocystis sp. PCC 6803 and determined its nucleotide sequence. Using an antibiotic-resistance cartridge to disrupt and replace the psbI gene, we have created mutants of Synechocystis 6803 that lack the PsbI protein. Analysis of these mutants revealed that absence of the PsbI protein results in a 25-30% loss of PSII activity. However, other PSII polypeptides are present in near wild-type amounts, indicating that no significant destabilization of the PSII complex has occurred. These results contrast with recently reported data indicating that PsbI-deficient mutants of the eukaryotic alga Chlamydomonas reinhardtii are highly light-sensitive and have a significantly lower (80-90%) titer of the PSII complex. In Synechocystis 6803, PsbI-deficient cells appear to be slightly more photosensitive than wild-type cells, suggesting that this protein, while not essential for PSII biogenesis or function, plays a role in the optimization of PSII activity.

Original languageEnglish
Pages (from-to)622-628
Number of pages7
JournalMGG Molecular & General Genetics
Volume249
Issue number6
DOIs
StatePublished - Nov 1995

Keywords

  • Light sensitivity
  • Oxygen evolution
  • Photosynthesis
  • Photosystem II
  • Targeted mutagenesis

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