Synechocystis sp PCC 6803 Oxa1 Homolog Is Essential for Membrane Integration of Reaction Center Precursor Protein pD1

• Published in: The Plant cell Vol. 18; no. 9; pp. 2236 - 2246
• Main Authors: Ossenbühl, Friedrich, Inaba-Sulpice, Masami, Meurer, Jörg, Soll, Jürgen, Eichacker, Lutz A
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.09.2006
• Subjects: Antibodies; Bacterial Proteins - metabolism; Bacterial Proteins - physiology; Cell growth; Chlorophylls; Chloroplasts; Electron Transport; Fluorescence; Gels; Green Fluorescent Proteins - analysis; Light; Luminous intensity; Membrane Proteins - physiology; Molecular Sequence Data; Oxidation-Reduction; Photosynthetic Reaction Center Complex Proteins - metabolism; Photosystem II Protein Complex - metabolism; Plant cells; Protein Precursors - metabolism; Proteins; Quinones - metabolism; Recombinant Fusion Proteins - analysis; Synechocystis; Synechocystis - growth & development; Synechocystis - metabolism; Synechocystis - radiation effects; Thylakoids; Thylakoids - metabolism
• ISSN: 1040-4651; 1532-298X; 1532-298X
• DOI: 10.1105/tpc.106.043646

Synechocystis sp PCC 6803 Slr1471p, an Oxa1p/Alb3/YidC homolog, is an essential protein for cell viability for which functions in thylakoid membrane biogenesis and cell division have been proposed. Using a fusion of green fluorescent protein to the C terminus of Slr1471p, we found that the mutant slr1471-gfp is photochemically inhibited when light intensities increase to 80 μmol·m⁻²·s⁻¹. We show that photoinhibition correlates with an increased redox potential of the reaction center quinone QA⁻ and a decreased redox potential of QB⁻. Analysis reveals that membrane integration of the D1 precursor protein is affected, leading to the accumulation of pD1 in the membrane phase. We show that Slr1471p interacts directly with the D1 protein and discuss why the accumulation of pD1 in two reaction center assembly intermediates is dependent on Slr1471p.