Fig. 3: Staggered ionic locks and hydrophobic clusters stabilize intra- and inter-protomer interfaces.

(Center) In the cross-sectional view the face of the left proto-filament is represented as molecular surface with aliphatic, positively and negatively charged side chain atoms in yellow, blue, and red, respectively. (Left, right) Side chain contacts at the intra- and inter-protomer interfaces are visualized in separate panels to the left and right, respectively. Hydrophobic and hydrogen (H) bond as well as ionic contacts are shown as yellow and pink semi-transparent heavy lines. The backbone and side chain atoms of the opposing strands are represented in mixed cartoon/stick format in white with black outlines. Residue contacts at the inter-protomer interface are related by a two-fold symmetry axis, which is highlighted by black and gray residue labels. See Supplementary Fig. 6 for molecular footprints to illustrate staggered contacts.