For the amino acids, we distinguished only the aromatic and aliphatic regions (Figure ). The CHp stacking interactions involve favorable contributions from the aromatic ring(s) and multiple CH and OH groups on galactose (Figure ). They can also include one or more weakly repulsive interactions between the aromatic ring system and closely interacting CH groups from the galactose in which the repulsive exchange energy outweighs the favorable dispersion energy. As a result, optimizing the total energy of a CH-p stacking interaction can require a tradeoff where interacting atoms in too close proximity to the aromatic ring have energetics dominated by an unfavorable exchange repulsion energy that is offset by favorable dispersion and electrostatic energies of other, connected atoms (Figure ). Notably, the CH-p stacking interactions involve favorable contributions from more participating atoms on galactose than hydrogen bonding or other non-specific interactions, demonstrating the cohesive nature of the interactions (Figure ).