title: A 2D gel electrophoresis-based snapshot of the phosphoproteome in the cyanobacterium Synechocystis sp. strain PCC 6803.
abstract: Cyanobacteria are photoautotrophic prokaryotes that occur in highly variable environments. Protein phosphorylation is one of the most widespread means to adjust cell metabolism and gene expression to the demands of changing growth conditions. Using a 2D gel electrophoresis-based approach and a phosphoprotein-specific dye, we investigated the protein phosphorylation pattern in cells of the model cyanobacterium Synechocystis sp. strain PCC 6803. The comparison of gels stained for total and phosphorylated proteins revealed that approximately 5 % of the protein spots seemed to be phosphoproteins, from which 32 were identified using MALDI-TOF MS. For eight of them the phosphorylated amino acid residues were mapped by subsequent mass spectrometric investigations of isolated phosphopeptides. Among the phosphoproteins, we found regulatory proteins, mostly putative anti-sigma factor antagonists, and proteins involved in translation. Moreover, a number of enzymes catalysing steps in glycolysis or the Calvin-Benson cycle were found to be phosphorylated, implying that protein phosphorylation might represent an important mechanism for the regulation of the primary carbon metabolism in cyanobacterial cells.
authors.affiliation: Core Facility Proteomanalytik, Universitätsmedizin, Universität Rostock, Schillingallee 69, 18057 Rostock, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Mikkat
authors.affiliation: Zellphysiologie, Institut Biowissenschaften, Universität Rostock, Albert-Einstein-Str. 3, 18051 Rostock, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Fulda
authors.affiliation: Pflanzenphysiologie, Institut Biowissenschaften, Universität Rostock, Albert-Einstein-Str. 3, 18051 Rostock, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hagemann
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional; D010750:Phosphoproteins / Q000032:analysis*; D020543:Proteome / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013194:Staining and Labeling; D046939:Synechocystis / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D010750:Phosphoproteins; D020543:Proteome