Histidine residue 252 of the Photosystem II D1 polypeptide is involved in a light-induced cross-linking of the polypeptide with the α subunit of cytochrome b-559: Study of a site-directed mutant of Synechocystis PCC 6803

Lenka Lupínková, James G. Metz, Bruce A. Diner, Imre Vass, Josef Komenda

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Properties of the Photosystem II (PSII) complex were examined in the wild-type (control) strain of the cyanobacterium Synechocystis PCC 6803 and its site-directed mutant D1-His252Leu in which the histidine residue 252 of the D1 polypeptide was replaced by leucine. This mutation caused a severe blockage of electron transfer between the PSII electron acceptors QA and QB and largely inhibited PSII oxygen evolving activity. Strong illumination induced formation of a D1-cytochrome b-559 adduct in isolated, detergent-solubilized thylakoid membranes from the control but not the mutant strain. The light-induced generation of the adduct was suppressed after prior modification of thylakoid proteins either with the histidine modifier platinum-terpyridine-chloride or with primary amino group modifiers. Anaerobic conditions and the presence of radical scavengers also inhibited the appearance of the adduct. The data suggest that the D1-cytochrome adduct is the product of a reaction between the oxidized residue His252 of the D1 polypeptide and the N-terminal amino group of the cytochrome α subunit. As the rate of the D1 degradation in the control and mutant strains is similar, formation of the adduct does not seem to represent a required intermediary step in the D1 degradation pathway.

Original languageEnglish
Pages (from-to)192-201
Number of pages10
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1554
Issue number3
DOIs
Publication statusPublished - Jul 1 2002

Keywords

  • Cyanobacterium
  • Cytochrome b-559
  • D1 polypeptide
  • Photoinhibition
  • Photosystem II
  • Synechocystis PCC 6803

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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