Fig. S2.

Hydrogen atom positions are revealed by a σ_A weighted F_o − F_c map. (A) The residual map is contoured at +3.0 σ (green) and −3.0 σ (red). The map was calculated by using phases from a model of GNNQQNY (P2₁2₁2₁), which had no hydrogens included, nor had any hydrogens been introduced at any point leading to this model. (B) GNNQQNY with hydrogen atoms (black) modeled in riding positions. All of these peaks (20) are within 1.0 Å of the geometrically positioned hydrogen atoms and are labeled by the hydrogen atom. These account for 42% of the total hydrogen atoms present. No hydrogen atoms were detected on water molecules (cyan spheres).