The unusual properties of the photosynthetic cytochrome c550 from the red algal lineage evidence additional biological roles
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ABSTRACT: Cytochrome c550 is an extrinsic component in the luminal side of photosystem II in cyanobacteria, as well as in eukaryotic algae from the red photosynthetic lineage including, among others, diatoms. By using strong and specific protease inhibitors we have confirmed that cytochrome c550 from the diatom Phaeodactylum tricornutum is expressed as a truncated form lacking the last hydrophobic residues at the C-terminal.. Phaeodactylum tricornutum cytochrome c550 seems to be modified at a post-translational level as the gene is appropriately transcribed. In addition, co-immunoprecipitation and mass spectrometry experiments have allowed the identification of novel interactions of Phaeodactylum tricornutum cytochrome c550 with proteins related to the CO2 concentrating mechanism and assimilation located in the chloroplast pyrenoid. Furthermore, immunoelectron microscopy analysis indicates that although cytochrome c550 is mainly located in the thylakoid domain of the chloroplast, it can also be found in the pyrenoid. The results are interpreted in terms of a specific protein modification associated to a higher PSII turnover or to new alternative functions of the heme protein, maybe related to carbon fixation.
INSTRUMENT(S): TripleTOF 5600
ORGANISM(S): Phaeodactylum Tricornutum
SUBMITTER: Jose Antonio Navarro
LAB HEAD: Jose Antonio Navarro Carruesco
PROVIDER: PXD008763 | Pride | 2022-03-03
REPOSITORIES: Pride
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