title: Isolation of a novel oil globule protein from the green alga Haematococcus pluvialis (Chlorophyceae).
abstract: 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.
authors: Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990, Sede boker campus, Israel.
authors: Ehud
authors: E
authors: Peled
authors: Stefan
authors: S
authors: Leu
authors: Aliza
authors: A
authors: Zarka
authors: Meira
authors: M
authors: Weiss
authors: Uri
authors: U
authors: Pick
authors: Inna
authors: I
authors: Khozin-Goldberg
authors: Sammy
authors: S
authors: Boussiba
mesh_terms: D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000378:metabolism; D000460:Chlorophyta; D002851:Chromatography, High Pressure Liquid; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D015870:Gene Expression; D057927:Hydrophobic and Hydrophilic Interactions; D008969:Molecular Sequence Data; D010936:Plant Extracts / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D016415:Sequence Alignment; D024341:Xanthophylls / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D005227:Fatty Acids; D010936:Plant Extracts; D010938:Plant Oils; D010940:Plant Proteins; D024341:Xanthophylls; D002734:Chlorophyll; C005948:astaxanthine