Fig. 1 in Tropical vibes from Sri Lanka - cyclotides from Viola betonicifolia by transcriptome and mass spectrometry analysis

Fig. 1. Example structures and sequences from the three main cyclotide subfamilies. The structures are based on the PDB files for kalata B1 (1nb1), cycloviolacin O1 (1nbj) and Momordica cochinchinensis II (MCoTI-II) (1ib9). The unique cyclic cystine knot (CCK) topology of cyclotides arises when the ring formed by CysI-CysIV and CysII-CysV together with the backbone loops 1 and 4 are penetrated by the third disulfide between CysIII and CysVI. The cyclotide producing plant families are denoted by RRubiaceae VViolaceae, FFabaceae, SSolanaceae and CCucurbitaceae. The conserved Cys residues are highlighted in yellow and the cis-pro in loop 5 that defines the M¨obius subfamily is highlighted in blue. The conserved Asn/Asp residue at which cyclisation occurs is highlighted in red. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)