Supplementary data to "Ligand binding site structure shapes allosteric signal transduction and the evolution of allostery in protein complexes" by G. Abrusan and J.A. Marsh

The structure of ligand binding sites has been shown to profoundly influence the evolution of function in homomeric protein complexes. Complexes with multi-chain binding sites (MBSs) have more conserved quaternary structure, more similar binding sites and ligands between homologues, and evolve new functions slower than homomers with single-chain binding sites (SBSs). Here, using in silico analyses of protein dynamics, we investigate whether ligand binding-site structure shapes allosteric signal transduction pathways (STPs), and whether the structural similarity of binding sites influences the evolution of allostery. Our analyses show that: 1) allostery is more frequent among MBS complexes than in SBS complexes, particularly in homomers; 2) in MBS homomers, semi-rigid communities and critical residues frequently connect interfaces and thus they are characterized by STPs that cross protein-protein interfaces, while SBS homomers usually not; 3) ligand binding alters community structure differently in MBS and SBS homomers; 4) allosteric proteins are more likely to have homologs with similar binding site than non-allosteric proteins, suggesting that binding site similarity is an important factor driving the evolution of allostery.