Profiling Chlamydomonas Metabolism under Dark, Anoxic H2-Producing Conditions Using a Combined Proteomic, Transcriptomic, and Metabolomic Approach

Venkataramanan Subramanian, Alexandra Dubini, Lieve Laurens, David Astling, William Old, Arthur Gorssman, Matthew Posewitz, Michael Seibert

Research output: Contribution to journalArticlepeer-review

20 Scopus Citations

Abstract

Chlamydomonas reinhardtii is well adapted to survive under different environmental conditions due to the unique flexibility of its metabolism. Here we report metabolic pathways that are active during acclimation to anoxia, but were previously not thoroughly studied under dark, anoxic H2-producing conditions in this model green alga. Proteomic analyses, using 2D-differential in-gel electrophoresis in combination with shotgun mass fingerprinting, revealed increased levels of proteins involved in the glycolytic pathway downstream of 3-phosphoglycerate, the glyoxylate pathway, and steps of the tricarboxylic acid (TCA) reactions. Upregulation of the enzyme, isocitrate lyase (ICL), was observed, which was accompanied by increased intracellular succinate levels, suggesting the functioning of glyoxylate pathway reactions. The ICL-inhibitor study revealed presence of reverse TCA reactions under these conditions. Contributions of the serine-isocitrate lyase pathway, glycine cleavage system, and c1-THF/serine hydroxymethyltransferase pathway in the acclimation to dark anoxia were found. We also observed increased levels of amino acids (AAs) suggesting nitrogen reorganization in the form of de novo AA biosynthesis during anoxia. Overall, novel routes for reductant utilization, in combination with redistribution of carbon and nitrogen, are used by this alga during acclimation to O2 deprivation in the dark.

Original languageAmerican English
Pages (from-to)5431-5451
Number of pages21
JournalJournal of Proteome Research
Volume13
Issue number12
DOIs
StatePublished - 5 Dec 2014

Bibliographical note

Publisher Copyright:
© 2014 American Chemical Society.

NREL Publication Number

  • NREL/JA-2700-61785

Keywords

  • amino acid synthesis
  • Chlamydomonas reinhardtii
  • glyoxylate pathway
  • hydrogen production
  • isocitrate lyase
  • proteomics
  • TCA reactions

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