126GLN IS THE RESIDUE OF HUMAN IL-2 BINDING TO IL-2R GAMMA-SUBUNIT

The 126Gln of human interleukin-2 (IL-2) is a conserved amino acid res idue. After substitution of 126Gln with Asp, the binding abilities of this mutant to different composites of IL-2 receptor (R) subunits have been determined. Results show that 126Asp-IL-2 has higher affinity to IL-2R alpha beta gamma complex and normal affinity to IL-2R alpha bet a complex, but loses its binding ability to IL-2R beta gamma complex, demonstrating that the 126Gln is the residue of human IL-2 which binds to IL-2R gamma subunit.