Interaction of truncated human interferon gamma variants with the interferon gamma receptor: crucial importance of Arg-129.
Recombinant human interferon gamma (IFN-gamma), produced in Escherichia coli, was selectively truncated at its C-terminus with chymotrypsin, clostripain or plasmin. The C-terminal amino acid residues of the three truncated IFN-gamma variants were identified as Phe136, Arg129 and Lys128, indicating the removal of 7, 14 and 15 amino acid residues from the full-length molecule. The absence of seven C-terminal residues did not influence the binding of IFN-gamma to its receptor. In contrast, the truncation of 14 residues resulted in a decrease in the Ka value to 1/24, as determined by surface plasmon resonance analysis. The removal of one additional amino acid residue from the C-terminal region of IFN-gamma led to a marked loss of receptor-binding capacity and biological activity. These observations demonstrate that Arg129 is an essential part of a functionally important C-terminal IFN-gamma sequence that is involved in receptor interaction.
Haelewyn
J
J
Laboratory for Biochemistry, Katholieke Universiteit Leuven (KULeuven), Celestijnenlaan 200 G, B-3001 Leuven-Heverlee, Belgium.
Michiels
L
L
Verhaert
P
P
Hoylaerts
M F
MF
Witters
R
R
De Ley
M
M
D000998:Antiviral Agents / Q000494:pharmacology; D001120:Arginine / Q000737:chemistry*; D001665:Binding Sites; D004686:Encephalomyocarditis virus / Q000187:drug effects / Q000502:physiology; D010450:Endopeptidases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008175:Lung Neoplasms / Q000473:pathology; D013058:Mass Spectrometry; D010446:Peptide Fragments / Q000378:metabolism*; D011485:Protein Binding; D017471:Receptors, Interferon / Q000378:metabolism*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured; D014779:Virus Replication / Q000187:drug effects; D000096743:Interferon gamma Receptor
D000998:Antiviral Agents; D001120:Arginine; D010450:Endopeptidases; D007371:Interferon-gamma; D010446:Peptide Fragments; D017471:Receptors, Interferon; D011994:Recombinant Proteins; D000096743:Interferon gamma Receptor