An intermolecular disulfide‐based light switch for chloroplast psbD gene expression in Chlamydomonas reinhardtii
Expression of the chloroplast psbD gene encoding the D2 protein of the photosystem II reaction center is regulated by light. In the green alga Chlamydomonas reinhardtii, D2 synthesis requires a high‐molecular‐weight complex containing the RNA stabilization factor Nac2 and the translational activator RBP40. Based on size exclusion chromatography analyses, we provide evidence that light control of D2 synthesis depends on dynamic formation of the Nac2/RBP40 complex. Furthermore, 2D redox SDS–PAGE assays suggest an intermolecular disulfide bridge between Nac2 and Cys11 of RBP40 as the putative molecular basis for attachment of RBP40 to the complex in light‐grown cells. This covalent link is reduced in the dark, most likely via NADPH‐dependent thioredoxin reductase C, supporting the idea of a direct relationship between chloroplast gene expression and chloroplast carbon metabolism during dark adaption of algal cells.
Document Type: Research Article
Affiliations: 1: Molekulare Pflanzenwissenschaften, Biozentrum Ludwig Maximilian University Munich, Grosshaderner Straße 2–4, 82152 Planegg-Martinsried, Germany 2: Instituto de Bioquimica Vegetal y Fotosintesis, University of Seville and Consejo Superior de Investigaciones Cientificas, Avenida Americo Vespucio 49, 41902 Seville, Spain
Publication date: November 1, 2012