The evolution and genetics of small cyclic peptides in plant seeds

Two groups of homodetic cyclic peptides were investigated. The first was the PawL-derived peptides (PLPs), which evolved within precursors for seed storage proteins in the sunflower family about 45 million years ago. Fifty three such peptides were characterised by mass spectrometry and six structures modelled with nuclear magnetic resonance spectroscopy. The second group of peptides described here is the annomuricatins, orbitides which are found in the soursop, Annona muricata. Six short transcripts encoding ten annomuricatins were characterised, which are interesting in that most of them code for two different peptides. The presence of the peptides was confirmed by mass spectrometry.