FIGURE 6.

Conservation of Fc-region residues between human IgA and chicken IgY. Shown is amino acid sequence alignment of the Cα2 and Cα3 domains of human IgA1 and IgA2 (accession numbers P01876-1 and P01877-1) and the Cυ3 and Cυ4 domains of chicken IgY (accession number X07174), performed using ClustalW (36). Residues in IgA1 that contact FcαRI in the crystal structure of the complex (Protein Data Bank code 1OW0) and their conserved equivalents in IgA2 and IgY sequences are shown in green; semi-conserved residues (i.e. residues with similar properties) are shown in blue.