Figure 6.

Panel A: super-imposition of the structural models obtained for T. hirsuta mytilin 1, 2 and 3. Panels B and C: structural models of Perna mytilins characterized by the presence of a canonical and an alternative cysteine array, respectively; the variable position of the C1–C5 disulfide bond is highlighted in red. Panels D and E schematic organization of the disulfide bond topology of mytilins with a canonical and alternative cysteine array, respectively. Panels F and G: alternative structural variants for M. galloprovincialis mytilin K, with two different sterically allowed C1–C5 disulfide bonds, highlighted in red. Panel H: structural model of a Perna defensin, with the side chain of the central cysteine residue of the CCC motif pointing outwards, highlighted in red.