11beta-alkyl-Delta9-19-nortestosterone derivatives: high-affinity ligands and potent partial agonists of the androgen receptor.

We report the synthesis of novel steroidal androgen receptor ligands comprising 11beta-alkyl-Delta(9)-derivatives of 19-nortestosterone. These compounds are structurally related to the antiprogestin, antiglucocorticoid, and antiandrogen drug mifepristone (RU486). Nortestosterone analogues bearing 11beta-octyl and 11beta-decyl side-chains bind tightly to recombinant AR protein (IC(50) = 6.

Facile synthesis of cids: biotinylated estrone oximes efficiently heterodimerize estrogen receptor and streptavidin proteins in yeast three hybrid systems.

[structure: see text] We synthesized estrone oximes as chemical inducers of protein heterodimerization (CIDs). Estrone-17-(O-carboxymethyl)oxime coupled to biotinamidocaproic acid via N,N'-dimethylhexane-1,6-diamine efficiently heterodimerizes estrogen receptors (ERs) and streptavidin Y43A in yeast three hybrid systems, activating gene expression over 100-fold at 10 microM. Related hexane-1,6-diamine and estradiol-6-(O-carboxymethyl)oxime derivatives were ineffective CIDs due to low affinity for ERs when bound to streptavidin.

Fluorescent cellular sensors of steroid receptor ligands.

Steroid hormone receptors comprise a major class of therapeutic drug targets that control gene expression by binding steroid hormone ligands. These small molecule-protein interactions are typically characterized in living cells by quantification of ligand-mediated reporter gene expression. As an alternative, non-transcriptional approach, we constructed fluorescent cellular sensors by expressing yellow fluorescent protein (YFP) fused to the ligand binding domains (LBDs) of estrogen receptor-alpha (ERalpha), estrogen receptor-beta (ERbeta), androgen receptor (AR), and the glucocorticoid receptor (GR).

Synthesis of a beta-estradiol-biotin chimera that potently heterodimerizes estrogen receptor and streptavidin proteins in a yeast three-hybrid system.

Small molecules that dimerize proteins in living cells provide powerful probes of biological processes and have potential as tools for the identification of protein targets of natural products. We synthesized 7-alpha-substituted derivatives of beta-estradiol tethered to the natural product biotin to regulate heterodimerization of estrogen receptor (ER) and streptavidin (SA) proteins expressed as components of a yeast three-hybrid system. Addition of an estradiol-biotin chimera bearing a 19-atom linker to yeast expressing DNA-bound ER-alpha or ER-beta LexA fusion proteins and wild-type SA protein fused to the B42 activation domain activated reporter gene expression by as much as 450-fold in vivo (10 muM ligand).