Molecular model of the N-terminal IgV set domain of human CEACAM1/BGP.

Ribbon diagram of the N-terminal domain of CEACAM1 showing the predicted homophilic interface. The β strands are labeled A to G according to convention. The GFCC′C" face is in gold and the ABED face is in cyan. The mutated amino acids analyzed in the adhesion assays are indicated on the model according to the one-letter amino acid code. Particularly noticeable are the amino acids in CC′ and FG loops, which protrude from the IgV domain. The conserved intradomain salt bridge R64 (light blue) and D82 (red) can be clearly seen to link the base of the D and F strands.