Figure 5. 4-tuples of inter-protein contact sites.

In the 4-tuples, the dotted edges stand for inter-protein contacts, while the solid edges are the intra-protein contacts. The subversion k of category X is named Xk. e.g the sub-version 1 of type A is named A1. A. The observed relative frequencies. B. Relative frequencies of 4-tuple subversions at interfaces.