1t83
CRYSTAL STRUCTURE OF A HUMAN TYPE III FC GAMMA RECEPTOR IN COMPLEX WITH AN FC FRAGMENT OF IGG1 (ORTHORHOMBIC)
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OverviewOverview
Fcgamma receptors mediate antibody-dependent inflammatory responses and, cytotoxicity as well as certain autoimmune dysfunctions. Here we report, the crystal structure of a human Fc receptor (FcgammaRIIIB) in complex, with an Fc fragment of human IgG1 determined from orthorhombic and, hexagonal crystal forms at 3.0- and 3.5-A resolution, respectively. The, refined structures from the two crystal forms are nearly identical with no, significant discrepancies between the coordinates. Regions of the, C-terminal domain of FcgammaRIII, including the BC, C'E, FG loops, and the, C' beta-strand, bind asymmetrically to the lower hinge region, residues, Leu(234)-Pro(238), of both Fc chains creating a 1:1 receptor-ligand, stoichiometry. Minor conformational changes are observed in both the, receptor and Fc upon complex formation. Hydrophobic residues, hydrogen, bonds, and salt bridges are distributed throughout the receptor.Fc, interface. Sequence comparisons of the receptor-ligand interface residues, suggest a conserved binding mode common to all members of, immunoglobulin-like Fc receptors. Structural comparison between, FcgammaRIII.Fc and FcepsilonRI.Fc complexes highlights the differences in, ligand recognition between the high and low affinity receptors. Although, not in direct contact with the receptor, the carbohydrate attached to the, conserved glycosylation residue Asn(297) on Fc may stabilize the, conformation of the receptor-binding epitope on Fc. An, antibody-FcgammaRIII model suggests two possible ligand-induced receptor, aggregations.
About this StructureAbout this Structure
1T83 is a Protein complex structure of sequences from Homo sapiens with as ligand. This structure superseeds the now removed PDB entry 1IIS. Full crystallographic information is available from OCA.
ReferenceReference
The structure of a human type III Fcgamma receptor in complex with Fc., Radaev S, Motyka S, Fridman WH, Sautes-Fridman C, Sun PD, J Biol Chem. 2001 May 11;276(19):16469-77. Epub 2001 Jan 31. PMID:11297532
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