RESUMO
Fc receptors are transmembrane proteins, found on the surfaces of immune cells, that aid in the removal of foreign pathogens by binding to antibody-coated targets via the Fc regions of the antibodies. To identify sites on mouse FcgammaRIII (moFcgammaRIII) alpha-chain that bind to the Fc region, peptides derived from the proximal extracellular domain (EC2) of moFcgammaRIII alpha-chain corresponding to the homologous region of human FcgammaRIIIB alpha-chain were synthesized. Binding of mouse IgG to the different peptides was tested by Dot-blot assay. The effective peptide (119)SFFHNEKSVRYH(130) located in the putative C-C' loop of the EC2 domain was found to bind mouse IgG specifically with an affinity of approximately 5.58 x 10(-5) M and inhibit the binding of mouse IgG to the receptor. Such a functional peptide should be very useful for further understanding the IgG-FcgammaR interaction and development of FcR-targeting drugs.