Identification and Functional Characterization of the 2-Hydroxy Fatty N-Acyl-Δ3(E)-desaturase from Fusarium graminearum

• Published in: The Journal of biological chemistry Vol. 283; no. 52; pp. 36734 - 36742
• Main Authors: Zaüner, Simone, Zähringer, Ulrich, Lindner, Buko, Warnecke, Dirk, Sperling, Petra
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 26.12.2008; American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M807264200

Δ3(E)-Unsaturated fatty acids are characteristic components of glycosylceramides from some fungi, including also human- and plant-pathogenic species. The function and genetic basis for this unsaturation is unknown. For Fusarium graminearum, which is pathogenic to grasses and cereals, we could show that the level of Δ3-unsaturation of glucosylceramide (GlcCer) was highest at low temperatures and decreased when the fungus was grown above 28 °C. With a bioinformatics approach, we identified a new family of polypeptides carrying the histidine box motifs characteristic for membrane-bound desaturases. One of the corresponding genes was functionally characterized as a sphingolipid-Δ3(E)-desaturase. Deletion of the candidate gene in F. graminearum resulted in loss of the Δ3(E)-double bond in the fatty acyl moiety of GlcCer. Heterologous expression of the corresponding cDNA from F. graminearum in the yeast Pichia pastoris led to the formation of Δ3(E)-unsaturated GlcCer.