Cucurbit[8]uril is a potent, low toxicity and orally active supramolecular inducer of protein heterodimerization. Cucurbit[8]uril induces heterodimerization of methylviologen and naphthalene functionalized proteins. Cucurbit[8]uril can induce energy transfer [1][2].

Cucurbit[8]uril (0~20 μM; 48 hours; CHO-K1 cells) makes the relative cell viability dropped marginally to 86%[2].Cucurbit[8]uril indeed selectively induces the heterodimerization of MV-eYFP with Np-eCFP. Cucurbit[8]uril-induced high energy transfer between the proteins is only observed in the presence of all three supramolecular components, allowing the formation of the ternary complex. In the presence of Cucurbit[8]uril, the unspecific protein assembly induced by the methylviologen is inhibited. The ternary system of Cucurbit[8]uril with methylviologen (MV) and naphthalene (NP) can also be successfully used for the formation of selective protein heterodimers of more hydrophobic proteins. The presence of Cucurbit[8]uril as a host molecule is required to prevent MV induced unspecific dimerization with hydrophobic protein surfaces[1].

Cucurbit[8]uril shows a very low toxicity of the in vivo intravenous injection, as well as oral administration studies on mice[2].

[1]. Uhlenheuer DA, et al. Cucurbit[8]uril induced heterodimerization of methylviologen and naphthalene functionalized proteins. Chem Commun (Camb). 2011;47(24):6798-6800.
[2]. Uzunova VD, et al. Toxicity of cucurbit[7]uril and cucurbit[8]uril: an exploratory in vitro and in vivo study. Org Biomol Chem. 2010;8(9):2037-2042.