Fig. 4. Cohesive FG–FG interactions at high resolution.

a, Interactions of F102 with other phenylalanine residues from different chains and layers (shown in different colours) in pm1. The parameter i refers to the layer of the reference residue F102 (shown in green), i – 1 and i – 2 refer to the layers above the reference, and i + 1, i + 2, i + 3 and i + 4 to the layers below it. Associated cryo-EM densities are displayed. The dashed lines show F102 contacts below 5 Å. b, Selected views of glutamine-asparagine polar contacts (dashed lines, 4 Å cut-off; top) and major phenylalanine-rich clusters (5 Å cut-off; bottom) in pm1–4.