Figure 3.

LK₇β is a peptide (Ac-LKLKLKL-NH₂) that assembles into antiparallel β-sheets at the air-water interface. Leucine residues are in yellow, lysine residues are in blue, and water molecules in the computational model are red. The polar lysine residues face into the aqueous phase, while the hydrophobic leucine residues face into the vacuum. LK₇β is modeled as a five-strand β-sheet with ~1350 water molecules around it. LE₇β forms the same structure (Figure S7), but with negatively charged glutamate residues facing the solvent instead of positively charged lysines.