Critical role of chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism

Wenqiang Yang, Tyler M. Wittkopp, Xiaobo Li, Jaruswan Warakanont, Alexandra Dubini, Claudia Catalanotti, Rick G. Kim, Eva C.M. Nowack, Luke C.M. Mackinder, Munevver Aksoy, Mark Dudley Page, Sarah D'Adamof, Shai Saroussi, Mark Heinnickel, Xenie Johnson, Pierre Richaud, Jean Alric, Marko Boehm, Martin C. Jonikas, Christoph BenninghSabeeha S. Merchant, Matthew C. Posewitz, Arthur R. Grossman

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Photosynthetic microorganisms typically have multiple isoforms of the electron transfer protein ferredoxin, although we know little about their exact functions. Surprisingly, a Chlamydomonas reinhardtii mutant null for the ferredoxin-5 gene (FDX5) completely ceased growth in the dark, with both photosynthetic and respiratory functions severely compromised; growth in the light was unaffected. Thylakoid membranes in dark-maintained fdx5 mutant cells became severely disorganized concomitant with a marked decrease in the ratio of monogalactosyldiacylglycerol to digalactosyldiacylglycerol, major lipids in photosynthetic membranes, and the accumulation of triacylglycerol. Furthermore, FDX5 was shown to physically interact with the fatty acid desaturases CrÎ"4FAD and CrFAD6, likely donating electrons for the desaturation of fatty acids that stabilize monogalactosyldiacylglycerol. Our results suggest that in photosynthetic organisms, specific redox reactions sustain dark metabolism, with little impact on daytime growth, likely reflecting the tailoring of electron carriers to unique intracellular metabolic circuits under these two very distinct redox conditions.

Original languageEnglish (US)
Pages (from-to)14978-14983
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number48
StatePublished - Dec 1 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


  • Dark growth
  • Ferredoxin
  • Redox regulation
  • Thylakoid lipids
  • Triacylglycerol


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