Global proteomic characterization of photosystem II complexes from Synechocystis 6803

In this study, we undertook a global proteomics analysis of isolated PSII complexes, comparing protein profiles of HT3 (C-terminal hexahistidine tagged CP47 protein) to those of deltaPsbV HT3, deltaPsbP HT3, and deltaPsbQ HT3. The sensitivity of these techniques allowed for identification of not only stoichiometric components of active PSII complexes, but also for the identification of proteins that are transiently associated with PSII throughout its lifecycle, such as assembly, repair, or degradation partners. From the results, we identified an operon of unknown function which contains binding domains for photosynthetic cofactors and which we have named the cofactor integration operon (cio). Upon deletion of the operon, photosynthetic capacity is decreased, indicating a function in PSII-mediated activity. Keywords: proteomic, photosystem II, cyanobacteria Comparison of wild type (HT3) to 3 mutants (deltaPsbV HT3, delataPsbP HT3, and deltaPsbQ HT3)