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A New Ligand for Immunoglobulin G Subdomains by Screening of a Synthetic Peptide Library
Author(s) -
Verdoliva Antonio,
Marasco Daniela,
De Capua Antonia,
Saporito Angela,
Bellofiore Piero,
Manfredi Vincenzo,
Fattorusso Roberto,
Pedone Carlo,
Ruvo Menotti
Publication year - 2005
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200400368
Subject(s) - tripeptide , peptide , chemistry , antibody , polyclonal antibodies , ligand (biochemistry) , monoclonal antibody , receptor , peptide sequence , peptide library , amino acid , biochemistry , combinatorial chemistry , stereochemistry , biology , immunology , gene
By screening a synthetic peptide library of general formula (NH 2 ‐Cys1‐X2‐X3‐X4) 2 ‐Lys‐Gly‐OH, a disulfide‐bridged cyclic peptide, where X2‐X3‐X4 is the tripeptide Phe‐His‐His, has been selected as a ligand for immunoglobulin G (IgG). The peptide, after a preliminary chromatographic characterization, has proved useful as a new affinity ligand for the purification of polyclonal as well as monoclonal antibodies from biological fluids, with recovery yields of up to 90 % (90 % purity). The ligand is able to bind antibody fragments containing both Fab and Fc from different antibody isotypes, a fact suggesting the presence of at least two different antibody‐binding sites. While the recognition site on Fab is unknown, comparative binding studies with Fc, in association with the striking similarities of the peptide (named Fc‐receptor mimetic, FcRM) with a region of the human FcγRIII receptor, strongly indicate that the peptide could recognize a short amino acid stretch of the lower hinge region, which has a key role in autoimmune disease triggering. The unique properties make the ligand attractive for both the purification of antibody fragments and as a lead for the generation of Fc‐receptor antagonists.