What is a protein-protein contrast?
A protein-protein contrast (PPC) is a contrast between two proteins. BioContrasts database contains contrasts between Swiss-Prot protein entries. Such contrast consists of three elements: a positive protein, a negative protein, and a biological activity. This contrast indicates that the positive protein but not the negative protein is involved in the activity. We call the proteins that are so contrasted, ‘focused proteins’, and the activity ‘presupposed property’. For example, the contrast between eIF4A (a positive protein) and eIF4E (a negative protein) with respect to the event of binding to NAT1 indicates that eIF4A but not eIF4E binds to NAT1.
