Fig. 4. (a) Overall structure of the zVDR LBD bound to the carborane 1 and the coactivator peptide. The stars indicate the insertion region not visible in the electron density map. (b) Overlay of 1,25D (carbon atoms in yellow and oxygen atoms in red) with 1 (violet) within zVDR LBD complexes. (c) The carborane 1 shown in the 2F _o–F _c electron density map contoured at 1σ.