The structure of the murine Fc receptor for IgG. Assignment of intrachain disulfide bonds, identification of N-linked glycosylation sites, and evidence for a fourth form of Fc receptor.
The Fc receptor (Fc gamma R) of the murine macrophage cell line, J774, was purified by immunoaffinity chromatography then subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and amino-terminal sequencing. FcR material judged to be pure by these criteria was digested with a number of enzymes to identify the cysteine residues engaged in disulfide bonds within the native structure. The results clearly establish that the mouse macrophage Fc gamma R contains two intrachain disulfide bonds, each of which connects adjacent cysteine residues within the two putative extracellular domains of the molecule. In addition, each disulfide-bonded domain was shown to contain two authentic sites of N-linked glycosylation. Extensive peptide sequencing resulted in the unexpected identification of peptide fragments from a fourth Fc gamma R whose sequences were highly homologous to sequences surrounding the two Cys residues in the amino-terminal domain of both alpha and beta 1 Fc gamma R. The fourth Fc gamma R contains a disulfide-bonded amino-terminal domain similar to beta 1 Fc gamma R.
D000595:Amino Acid Sequence; D000818:Animals; D002236:Carbohydrate Conformation; D002460:Cell Line; D004220:Disulfides; D014644:Genetic Variation; D006019:Glycolysis; D007074:Immunoglobulin G / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification*; D011487:Protein Conformation; D011961:Receptors, Fc / Q000302:isolation & purification*; D017452:Receptors, IgG; D013329:Structure-Activity Relationship
D004220:Disulfides; D007074:Immunoglobulin G; D010446:Peptide Fragments; D011961:Receptors, Fc; D017452:Receptors, IgG