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Crystal structure of the soluble human Fc-gamma Receptor III
Structural highlights
FunctionFCG3B_HUMAN Receptor for the Fc region of immunoglobulins gamma. Low affinity receptor. Binds complexed or aggregated IgG and also monomeric IgG. Contrary to III-A, is not capable to mediate antibody-dependent cytotoxicity and phagocytosis. May serve as a trap for immune complexes in the peripheral circulation which does not activate neutrophils. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe immune response depends on the binding of opsonized antigens to cellular Fc receptors and the subsequent initiation of various cellular effector functions of the immune system. Here we describe the crystal structures of a soluble Fc gamma receptor (sFc gammaRIII, CD16), an Fc fragment from human IgG1 (hFc1) and their complex. In the 1:1 complex the receptor binds to the two halves of the Fc fragment in contact with residues of the C gamma2 domains and the hinge region. Upon complex formation the angle between the two sFc gammaRIII domains increases significantly and the Fc fragment opens asymmetrically. The high degree of amino acid conservation between sFc gammaRIII and other Fc receptors, and similarly between hFc1 and related immunoglobulins, suggest similar structures and modes of association. Thus the described structure is a model for immune complex recognition and helps to explain the vastly differing affinities of other Fc gammaR-IgG complexes and the Fc epsilonRI alpha-IgE complex. The 3.2-A crystal structure of the human IgG1 Fc fragment-Fc gammaRIII complex.,Sondermann P, Huber R, Oosthuizen V, Jacob U Nature. 2000 Jul 20;406(6793):267-73. PMID:10917521[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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