Fig. 7. Enrichment of intermolecular tyrosine-proline interactions in simulated crowded environments.

a Absolute fractions of the top 10 residue-residue contacts in the multi-copy system. Below, the sequence logo corresponding to the composition of heptads in the full-length hCTD sequence is shown. b Position-resolved interaction matrix in hCTD heptads obtained for single-copy (intramolecular contacts) and multi-copy (intermolecular contacts) systems. A value given for each pair corresponds to the ratio of the frequency of a particular contact type in the pool of all contacts seen in MD and the same frequency in a randomized background. Contacts colored red are enriched, and those shown in blue are depleted. Only positions corresponding to the canonical heptad residues are considered for the analysis. c Distribution of intermolecular contact frequencies along the hCTD sequence, averaged over the 10 protein copies in multi-copy simulations. Sequence positions corresponding to Tyr and Pro residues are indicated with green and blue-filled circles, respectively. d Comparison of depletion/enrichment values for Tyr-Pro contacts in the inter molecular context (multi-copy systems) to those in the intra-molecular context (single-copy systems) estimated as a ratio between the observed and the expected fractions of contacts, with the latter being evaluated from the frequency of residues in question. The corresponding fractions of the contacts are indicated above bars. The results of hCTD simulations are shown in comparison to the statistics obtained for other disordered low-complexity proteins (LGE1²⁸, FUS), simulated using the same modeling framework.