Publications

• Isolation and characterization of genes from the marine microalga Pavlova salina encoding three front-end desaturases involved in docosahexaenoic acid biosynthesis.

  Zhou X.R., Robert S.S., Petrie J.R., Frampton D.M., Mansour M.P., Blackburn S.I., Nichols P.D., Green A.G., Singh S.P.

  The marine microalga Pavlova salina produces lipids containing approximately 50% omega-3 long chain polyunsaturated fatty acids (LC-PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Three cDNA sequences, designated PsD4Des, PsD5Des, PsD8Des, were isolated from P. salina and ... >> More

  The marine microalga Pavlova salina produces lipids containing approximately 50% omega-3 long chain polyunsaturated fatty acids (LC-PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Three cDNA sequences, designated PsD4Des, PsD5Des, PsD8Des, were isolated from P. salina and shown to encode three front-end desaturases with Delta4, Delta5 and Delta8 specificity, respectively. Southern analysis indicated that the P. salina genome contained single copies of all three front-end fatty acid desaturase genes. When grown at three different temperatures, analysis of fatty acid profiles indicated P. salina desaturation conversions occurred with greater than 95% efficiency. Real-Time PCR revealed that expression of PsD8Des was higher than for the other two genes under normal growth conditions, while PsD5Des had the lowest expression level. The deduced amino acid sequences from all three genes contained three conserved histidine boxes and a cytochrome b(5) domain. Sequence alignment showed that the three genes were homologous to corresponding desaturases from other microalgae and fungi. The predicted activities of these three front-end desaturases leading to the synthesis of LC-PUFA were also confirmed in yeast and in higher plants. << Less

  Phytochemistry 68:785-796(2007) [PubMed] [EuropePMC]

  This publication is cited by 7 other entries.

• A cytochrome b5-containing plastid-located fatty acid desaturase from Chlamydomonas reinhardtii.

  Zaeuner S., Jochum W., Bigorowski T., Benning C.

  Monogalactosyldiacylglycerol (MGDG) in Chlamydomonas reinhardtii and other green algae contains hexadeca-4,7,10,13-tetraenoic acid (16:4) in the glycerol sn-2 position. While many genes necessary for the introduction of acyl chain double bonds have been functionally characterized, the Δ4-desaturas ... >> More

  Monogalactosyldiacylglycerol (MGDG) in Chlamydomonas reinhardtii and other green algae contains hexadeca-4,7,10,13-tetraenoic acid (16:4) in the glycerol sn-2 position. While many genes necessary for the introduction of acyl chain double bonds have been functionally characterized, the Δ4-desaturase remained unknown. Using a phylogenetic comparison, a candidate gene encoding the MGDG-specific Δ4-desaturase from Chlamydomonas (CrΔ4FAD) was identified. CrΔ4FAD shows all characteristic features of a membrane-bound desaturase, including three histidine boxes and a transit peptide for chloroplast targeting. But it also has an N-terminal cytochrome b(5) domain, distinguishing it from other known plastid desaturases. Cytochrome b(5) is the primary electron donor for endoplasmic reticulum (ER) desaturases and is often fused to the desaturase domain in desaturases modifying the carboxyl end of the acyl group. Difference absorbance spectra of the recombinant cytochrome b(5) domain of CrΔ4FAD showed that it is functional in vitro. Green fluorescent protein fusions of CrΔ4FAD localized to the plastid envelope in Chlamydomonas. Interestingly, overproduction of CrΔ4FAD in Chlamydomonas not only increased levels of 16:4 acyl groups in cell extracts but specifically increased the total amount of MGDG. Vice versa, the amount of MGDG was lowered in lines with reduced levels of CrΔ4FAD. These data suggest a link between MGDG molecular species composition and galactolipid abundance in the alga, as well as a specific function for this fatty acid in MGDG. << Less

  Eukaryot. Cell 11:856-863(2012) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.