Phycobilisome truncation causes widespread proteome changes in Synechocystis sp. PCC 6803

PLoS One. 2017 Mar 2;12(3):e0173251. doi: 10.1371/journal.pone.0173251. eCollection 2017.

Abstract

In cyanobacteria such as Synechocystis sp. PCC 6803, large antenna complexes called phycobilisomes (PBS) harvest light and transfer the energy to the photosynthetic reaction centers. Modification of the light harvesting machinery in cyanobacteria has widespread consequences, causing changes in cell morphology and physiology. In the current study, we investigated the effects of PBS truncation on the proteomes of three Synechocystis 6803 PBS antenna mutants. These range from the progressive truncation of phycocyanin rods in the CB and CK strains, to full removal of PBS in the PAL mutant. Comparative quantitative protein results revealed surprising changes in protein abundances in the mutant strains. Our results showed that PBS truncation in Synechocystis 6803 broadly impacted core cellular mechanisms beyond light harvesting and photosynthesis. Specifically, we observed dramatic alterations in membrane transport mechanisms, where the most severe PBS truncation in the PAL strain appeared to suppress the cellular utilization and regulation of bicarbonate and iron. These changes point to the role of PBS as a component critical to cell function, and demonstrate the continuing need to assess systems-wide protein based abundances to understand potential indirect phenotypic effects.

MeSH terms

  • Bacterial Proteins / metabolism*
  • Biological Transport
  • Chromatography, High Pressure Liquid
  • Hydrogen-Ion Concentration
  • Iron / metabolism
  • Mutation
  • Nitrogen / metabolism
  • Phycobilisomes / metabolism*
  • Proteome*
  • Synechocystis / genetics
  • Synechocystis / metabolism*
  • Tandem Mass Spectrometry

Substances

  • Bacterial Proteins
  • Phycobilisomes
  • Proteome
  • Iron
  • Nitrogen

Grants and funding

This work was supported as part of the Photosynthetic Antenna Research Center (PARC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC 0001035. Work was performed in the Environmental Molecular Sciences Laboratory, a U. S. Department of Energy Office of Biological and Environmental Research national scientific user facility located at Pacific Northwest National Laboratory in Richland, Washington. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy under Contract No. DE-AC05-76RLO 1830. AYN has been partially supported by the National Science Foundation Graduate Research Fellowship Program (DGE-1143954).