A 25-kDa stretch of the extracellular domain of the human interferon gamma receptor is required for full ligand binding capacity.

摘要: We investigated which is the shortest fragment of interferon gamma receptor with ligand binding capacity. A recombinant soluble produced in Escherichia coli was subjected to controlled digestion several proteolytic enzymes. The fragments generated were assayed by four approaches for binding. 25-kDa polypeptide comprising residues 6-227 mature protein sequential trypsin and proteinase K. It identified as domain full capacity judged blots. further tested affinity chromatography. 15-kDa amino acids 94-227 endoproteinase Glu-C found bind low immobilized gamma. This fragment, does not show on blots, immunoprecipitated a complex anti-interferon antibodies. also competed radiolabeled cell surface when it mixture products, but after separation from cleaved rest molecule. probably carries ligand-binding or part it, lacks sequences essential stretch between 6 21 include any disulfide bonds seems be activity. revealed that cysteine 60 68 form bond.