Structural comparison of with ICAM-1, -2, -3, and LW antigen (ICAM-4). A, amino acid sequence alignment of with ICAMs and LW antigen. The amino acid sequence of human (domains I–V) was aligned with those of ICAM-1 (domains I–V) (8, 9), ICAM-2 (domains I and II) (10), ICAM-3 (domains I–V) (11, 12), and LW antigen (domains I and II) (13). The open circles denote the highly conserved Cys residues. The residues conserved in more than three of the five members (domains I and II) or more than two of the three (domains III–V) are highlighted. B, proposed model of the domain structure of ICAMs and LW antigen. Amino acid identities between the corresponding Ig-like domains of ICAMs and LW antigen are shown with Arabic numerals above the Ig-like domains, respectively. Individual Ig-like domains are numbered I–IX on the top. Extra- and intracellular orientations are indicated by NH2 and COOH on the protein chains, respectively. Intradomain disulfide bonds are represented by SS (Cited from [5]).
