MODULATION OF INTERLEUKIN-2 HIGH-AFFINITY BINDING TO HUMAN T-CELLS BYA PYRIMIDODIAZEPINE INSECT METABOLITE

An insect metabolite containing the little known pyrimido[4,5-b][1,4]d iazepine ring system has been found to act as an effective mimic of te trahydrobiopterin in its ability to modulate the affinity of interleuk in 2 (IL-2) for its receptors on human T cells. Semi-empirical molecul ar orbital calculations reveal that while tetrahydrobiopterin has cons iderable flexibility, the pyrimidodiazepine has rather few conformatio nal options and offers a useful model for exploring the nature of the pterin binding site.