title: Identification of a cytochrome b5-fusion desaturase responsible for the synthesis of triunsaturated sphingolipid long chain bases in the marine diatom Thalassiosira pseudonana.
abstract: Triunsaturated sphingolipid long chain bases (LCBs) have previously been reported in some specialised tissues of marine invertebrates. We report the presence of similar LCBs in the marine diatom Thalassiosira pseudonana and identify the cytochrome b5-fusion desaturase responsible for the introduction of the third double bond at the Δ10 position in d18:3Δ4,8,10. This study extends the catalytic repertoire of the cytochrome b5 fusion desaturase family, also indicating the presence of orthologues in other marine invertebrates. The function of these polyunsaturated sphingolipid LCBs is currently unknown but it was previously suggested that they play an essential role in primitive animals. The identification of the desaturase responsible for their synthesis paves the way for further studies.
authors.affiliation: Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
authors.forename: Louise V
authors.initials: LV
authors.lastname: Michaelson
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Markham
authors.forename: Simone
authors.initials: S
authors.lastname: Zäeuner
authors.forename: Midori
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.forename: Edgar B
authors.initials: EB
authors.lastname: Cahoon
authors.forename: Johnathan A
authors.initials: JA
authors.lastname: Napier
mesh_terms: D015786:Cytochromes b5 / Q000378:metabolism*; D017377:Diatoms / Q000737:chemistry / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D013107:Sphingolipids / Q000096:biosynthesis* / Q000737:chemistry
chemical_list: D013107:Sphingolipids; D015786:Cytochromes b5; D010088:Oxidoreductases; C115532:sphingolipid desaturase