The effect of the chemical modification in human Fc gamma fragment on protein A and Fc receptor binding.
The role of acidic side-chains on Fc gamma fragment in granulocyte receptor binding and in S. aureus protein A binding has been investigated by means of chemical modification. Alteration of a restricted number of carboxyl groups after 5 min of reaction is sufficient to abrogate the capacity of Fc to inhibit EA rosette formation by human neutrophils. More limited modification, which affects mainly the most exposed acidic chains, does not change receptor binding activity. In contrast, the interaction with protein A is largely unaffected, even under reaction conditions which are able to induce significant changes in the circular dichroism spectrum of Fc fragment. The results suggest that some acidic groups on Fc may be involved in the interaction with neutrophil receptor and that the binding to protein A and Fc receptor involves different sites.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002942:Circular Dichroism; D006801:Humans; D007141:Immunoglobulin Fc Fragments; D009504:Neutrophils / Q000378:metabolism; D011487:Protein Conformation; D011961:Receptors, Fc / Q000032:analysis*; D017452:Receptors, IgG; D012397:Rosette Formation; D012756:Sheep; D013205:Staphylococcal Protein A / Q000378:metabolism*
D000596:Amino Acids; D007141:Immunoglobulin Fc Fragments; D011961:Receptors, Fc; D017452:Receptors, IgG; D013205:Staphylococcal Protein A