Double receptor model

Girgis L, Davis MM, Fazekas de St Groth B The avidity spectrum of T cell receptor interactions accounts for T cell anergy in a double transgenic model. J Exp Med 1999 189 265-278. 

Compounds with cis double bonds in the side chain were in general found to be more potent and efficacious than their triple-bond congeners, both in in vivo and in in vitro functional assays [98, 106, 107]. QSAR models have been generated for the compounds with unsaturated [108] and l, l -dimethyl [96] side chains to determine more precisely the pharmacophoric requirements of the receptor. It is postulated that for optimum potency, the side chain must be of a suitable length and flexibility to have the ability to loop back so that its terminus is in proximity to the phenolic ring. The widely used, potency enhancing 1 - and 2 -methyl substituents would be expected to increase the tendency of the side chain to adopt a looped back, rather than an extended conformation. 

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