Cerebroside B1b has antiulcerogenic activity.

Here, fusaruside is clarified biosynthetically, and its efficacy-related 10,11-double bond can be generated under the regioselective catalysis of an unprecedented α?10(E)-sphingolipid desaturase (α?10(E)-SD). α?10(E)-SD shares 17.7% amino acid sequence similarity with a C9-unmethylated α?10-sphingolipid desaturase derived from a marine diatom, and 55.7% with α?8(E)-SD from Fusarium graminearum. Heterologous expression of α?10(E)-SD in Pichia pastoris has been established to facilitate a reliable generation of 1 through the α?10(E)-SD catalyzed desaturation of Cerebroside B (2), an abundant fungal sphingolipid. Site directed mutageneses show that the conserved histidines of α?10(E)-SD are essential for the 10,11-desaturation catalysis, which is also preconditioned by the C9-methylation of the substrate. Moreover, α?10(E)-SD confers improved survival and faster growth to fungal strains at low temperature and high salinity, in parallel with to higher contents of 1 in the mycelia.