Fig. 6. (A) A representative structure of four peptides in parallel alignment. For simplicity, only the protein backbone is shown, and the tyrosine and tryptophane moieties are shown in green and grey spheres, respectively. The structure is (i) stabilised by the π–π stacking interactions involving Tyr and Trp moieties, (ii) stabilised by hydrogen bonding interactions within the neighbouring peptides, and (iii) the peptides form β-sheet secondary structure during our MD simulations (as represented by the arrows). (B) In a similar manner to panel A, a 20-peptide sheet was built to study a stability of this more complex structure. Even after ca. 13 ns of MD simulation, the end point of our simulation showed that the π–π stacking and H-bonding interactions are not preserved among all Tyr and Trp moieties (highlighted in green and grey), despite the ability to preserve most of the β-sheets (yellow). (C) MD simulation (30 ns) of 40 peptides in the anti-parallel B–B zipper mode packing (stabilised by 194 ± 9 H-bonding interactions). (D) MD simulation (30 ns) of 40 peptides in the parallel B–B zipper mode packing (stabilised by 192 ± 9 H-bonding interactions). Panels C and D show the most stable arrangements of a 40-peptide double sheets; the non-stable packing variants are shown in Fig. S7 in the ESI.†.