Structural Similarity between SFTI-1 and the Inhibitory Arm of Bowman-Birk Inhibitors
(A) Sequence of the backbone cyclic and disulfide bonded SFTI-1 with the line joining Cys residues denoting a disulfide bond and the line joining Gly and Asp denoting the cyclic backbone. Circled numbers from SFTI-1 (Cys-3, Lys-5, Pro-8, Pro-9, and Cys-11) are aligned with the BBI WebLogo (B) and used to mark their locations within the structural overlay (C).
(B) WebLogo summary of 150 aligned short segments of BBIs.
(C) SFTI-1 (stick format) overlaid upon the inhibitory loops of 10 BBIs (line format).
(D) Angiosperm phylogeny based on rbcL sequences and adapted from Mylne et al. (2012). The families containing BBIs are shown (Fabaceae or legumes, and Poaceae or grasses). The phylogenetically separate position of the BBI-loop mimic sunflower SFTI-1 is also shown.