Predicting conformations and orientations of guests within a water soluble host: a molecular docking approach

In this study we have examined conformations and orientations of guests within a water-soluble host known by the trivial name Octa Acid (OA). Docking program Vina, which was originally developed for screening drug-like molecules, has been used to identify binding modes and affinities of select guest molecules with OA. Hydrophobic guests were encapsulated into the nonpolar cavity of OA capsule owing to solvophobic interactions. Amphiphilic guests were bound by keeping the nonpolar part within the cavity of OA, while pointing the polar anionic group out of the cavity. All these results obtained from the docking study were in accord with experimental findings. The post-complexation attributes of the guests were regulated by available free space and the specific interactions between guest–OA pair, which led to unusual conformations and orientations. This study showed that scoring function available with Vina, which was derived from protein–ligand data set, could successfully predict post-complexed structural features of guests within OA, thus opening opportunities to modulate physical and chemical behavior of guest molecules.