Poster Presentation The 45th Lorne Conference on Protein Structure and Function 2020

Circling back to 1955: biosynthesis of evolidine, the first plant cyclopeptide discovered (#402)

Joshua S Mylne 1 , Mark F Fisher 1 , Thaveshini Chetty 1
  1. The University of Western Australia, Perth, WA, Australia

Cyclic peptides have been reported to have antimicrobial, antifungal and many other bioactivities. Several plants in the citrus family (Rutaceae) family are known to produce orbitides, which are small head-to-tail cyclic peptides lacking disulfide bonds. One of these is the Australian rain forest tree Melicope xanthoxyloides, in which the first plant cyclic peptide, evolidine (cyclo-SFLPVNL), was discovered by Australian scientists Eastwood et al. in 1955. Evolidine was thereafter all but forgotten in the academic literature, yet we revisited this Aussie-first by using de novo transcriptomics to determine the biosynthetic origin for evolidine. It is encoded by a short transcript of ~250 nucleotides and comes from within a precursor protein just 46 residues in length. Other, similar transcripts also encode cyclic peptides, which we characterised by tandem mass spectrometry. Mining publicly available data for other species revealed a host of similar potential peptide-encoding sequences across the Rutaceae and probably beyond.

  1. Eastwood, Hughes, Ritchie & Curtis (1955) Aust. J. Chem. 8: 552-555.