Isolation of a Novel Oil Globule Protein from the Green Alga Haematococcus pluvialis (Chlorophyceae)

Ehud Peled, Stefan Leu, Aliza Zarka, Meira Weiss, Uri Pick, Inna Khozin-Goldberg, Sammy Boussiba

Research output: Contribution to journalArticlepeer-review


Cytoplasmic oil globules of Haematococcus pluvialis (Chlorophyceae) were isolated and analyzed for pigments, lipids and proteins. Astaxanthin appeared to be the only pigment deposited in the globules. Triacyglycerols were the main lipids (more than 90% of total fatty acids) in both the cell-free extract and in the oil globules. Lipid profile analysis of the oil globules showed that relative to the cell-free extract, they were enriched with extraplastidial lipids. A fatty acids profile revealed that the major fatty acids in the isolated globules were oleic acid (18:1) and linoleic acid (18:2). Protein extracts from the globules revealed seven enriched protein bands, all of which were possible globule-associated proteins. A major 33-kDa globule protein was partially sequenced by MS/MS analysis, and degenerate DNA primers were prepared and utilized to clone its encoding gene from cDNA extracted from cells grown in a nitrogen depleted medium under high light. The sequence of this 275-amino acid protein, termed the Haematococcus Oil Globule Protein (HOGP), revealed partial homology with a Chlamydomonas reinhardtii oil globule protein and with undefined proteins from other green algae. The HOGP transcript was barely detectable in vegetative cells, but its level increased by more than 100 fold within 12 h of exposure to nitrogen depletion/high light conditions, which induced oil accumulation. HOGP is the first oil-globule-associated protein to be identified in H. pluvialis, and it is a member of a novel gene family that may be unique to green microalgae.
Original languageEnglish
Pages (from-to)851-861
Number of pages11
Issue number9
StatePublished - 1 Sep 2011


  • Astaxanthin
  • Haematococcus
  • Oil globule protein
  • Oil globules
  • Triacylglycerols

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Organic Chemistry
  • Cell Biology


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