Fig. 4: Salt bridge knots flank the interruptions sites in human collagens.

Representative examples of salt bridge knots observed in human collagens containing two to six (A–E) and eight (F) salt bridges. Interacting pairs of lysine and aspartate/glutamate residues are shown in dark blue, the KGE and KGD triplets are shown in light purple and interruptions are shown in yellow. The interchain i → i + 2 salt bridges are shown with black line while the i → i + 5 salt bridges are shown in red. Although the representative examples shown in this figure contain interruptions only towards the C-termini, examples of salt bridge knots on the N-termini also abound (Supplementary Fig. 4).