Fig. 5 |. Illustration of the G metric and non-covalent lasso topology.

Bottom left, contact map of native contacts, where the top and bottom triangular regions represent the native contacts within the native crystal structure of CAT-III (top left) and one of the misfolded structures in state P13 (bottom right), respectively. The native contacts in the misfolded structure are coloured based on the linking number g, calculated using Supplementary Equation (16). Top right, topology diagram of the non-covalent lasso entanglement formed by the native contact of residues 167 and 183, as an instance, where the closed loop is shown in red and the threading segment is shown in blue. As described in equation (2), the G metric of this misfolded structure, G = 0.12, was calculated by counting the number of native contacts within the misfolded structure, whose g value is different from that of the same native contact within the crystal structure (that is, the number of native contacts covered by the black circles in the lower triangular region of the contact map, which is 55), and normalizing them to the total number of native contacts in the crystal structure (that is, G = 55/442 = 0.12).