VL/VH Dimer Interface

Given the combinatorial nature of antibody generation, the dimer interface residues have to be such that any VL domain can pair with any VH domain to form a functional interface. This places a heavy constraint on the conservation of the interface residues.

VL Dimer Contacts	VH Dimer Contacts

At the same time, there is considerable overlap between the antigen interface and the dimer interface, particularely for hapten-binding antibodies, where the antigen frequently inserts into a deep binding pocket in the center of the barrel formed by the inner beta sheets of the two domains.