Comparison of structural features between crosstalk (red) and negative pairs (blue). (A) Accessible shell volume. (B) Minimum inaccessible radius. (C) Pocketness. (D) Ollivier-Ricci curvature. (E) Multifractal dimension. (F) Circular variance. (G) OPD chirality index (calculated using N = 5, 7, 10, and 15). (H) Shortest path distance. Max, Min, and Ave represent the maximum, minimum, and average values of two residues in each PTM pair regarding a given attribute. The statistical significance is evaluated using the Wilcoxon rank sum test. ***P < 0.001, **P < 0.01, and *P < 0.05.