Two alternative perspectives of the 3D structure of human CD2 extracellular domain. Sites involved in CD58/CD48 binding are shown in blue. Codon sites (amino acids) predicted to be subject to positive selection from inter-specific comparison are shown in red. Yellow sites indicate the orthologous positions of nonsynonymous SNPs occurring within cattle populations. The structure was displayed using RasMol v22.214.171.124.1.