Complete biosynthesis of the potent vaccine adjuvant QS-21

QS-21 is a potent vaccine adjuvant currently sourced by extraction from the Chilean soapbark tree. It is a key component of human vaccines for shingles, malaria, coronavirus disease 2019 and others under development. The structure of QS-21 consists of a glycosylated triterpene scaffold coupled to a complex glycosylated 18-carbon acyl chain that is critical for immunostimulant activity. We previously identified the early pathway steps needed to make the triterpene glycoside scaffold; however, the biosynthetic route to the acyl chain, which is needed for stimulation of T cell proliferation, was unknown. Here, we report the biogenic origin of the acyl chain, characterize the series of enzymes required for its…

• JI
  John Innes Foundation

  Award: BBS/E/J/000PR9790
• DF
  Directorate for Biological Sciences
• BA
  Biotechnology and Biological Sciences Research Council

  Awards: BB/T015063/1, BB/R005508/1, BBS/E/J/000PR9790, BB/W017857/1, BBS/E/J/000PR9790, BBS/E/JI/230004B