1T83

CRYSTAL STRUCTURE OF A HUMAN TYPE III FC GAMMA RECEPTOR IN COMPLEX WITH AN FC FRAGMENT OF IGG1 (ORTHORHOMBIC)

Replaces:  1IIS

Summary for 1T83

• Entry DOI: 10.2210/pdb1t83/pdb
• Related: 1E4K 1F6A 1FNL 1IIS 1IIX 1T89
• Descriptor: IGG1, Low affinity immunoglobulin gamma Fc region receptor III-B, beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-6)-[beta-D-mannopyranose-(1-3)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[beta-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: fc gamma receptor, igg1, cd16, fcgriii, immunoglobulin, immune system
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 3
• Total formula weight: 73884.75

Authors

Radaev, S.,Motyka, S.,Fridman, W.-H.,Sautes-Fridman, C.,Sun, P.D. (deposition date: 2004-05-11, release date: 2004-09-28, Last modification date: 2024-10-30)

Primary citation

Radaev, S.,Motyka, S.,Fridman, W.-H.,Sautes-Fridman, C.,Sun, P.D.
The structure of a human type III Fcgamma receptor in complex with Fc
J.Biol.Chem., 276:16469-16477, 2001

PubMed Abstract: 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.

PubMed: 11297532
DOI: 10.1074/jbc.M100350200

Experimental method

X-RAY DIFFRACTION (3 Å)