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Fatty acid desaturases from the microalga Thalassiosira pseudonana
Author(s) -
To Thierry,
Sayanova Olga,
Michaelson Louise V.,
Qing Renwei,
Harvey David,
Larson Tony R.,
Li Yi,
Napier Johnathan A.,
Graham Ian A.
Publication year - 2005
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2005.04755.x
Subject(s) - thalassiosira pseudonana , biology , gene , fatty acid desaturase , polyunsaturated fatty acid , genome , phylogenetic tree , docosahexaenoic acid , cytochrome b5 , fatty acid , open reading frame , genetics , biochemistry , peptide sequence , cytochrome p450 , enzyme , phytoplankton , ecology , nutrient
Analysis of a draft nuclear genome sequence of the diatom Thalassiosira pseudonana revealed the presence of 11 open reading frames showing significant similarity to functionally characterized fatty acid front‐end desaturases. The corresponding genes occupy discrete chromosomal locations as determined by comparison with the recently published genome sequence. Phylogenetic analysis showed that two of the T. pseudonana desaturase ( Tpdes ) sequences grouped with proteobacterial desaturases that lack a fused cytochrome b5 domain. Among the nine remaining gene sequences, temporal expression analysis revealed that seven were expressed in T. pseudonana cells. One of these, TpdesN , was previously characterized as encoding a Δ 11 ‐desaturase active on palmitic acid. From the six remaining putative desaturase genes, we report here that three, TpdesI , TpdesO and TpdesK , respectively encode Δ 6 ‐, Δ 5 ‐ and Δ 4 ‐desaturases involved in production of the health beneficial polyunsaturated fatty acid DHA (docosahexaenoic acid). Furthermore, we show that one of the remaining genes, TpdesB , encodes a Δ 8 ‐sphingolipid desaturase with strong preference for dihydroxylated substrates.