Many large transmembrane protein receptors play vital roles in clinical applications. For instance, the nicotinic acetylcholine receptor (nAChR) can serve as a useful target in the efforts of smoking cessation, counter drug addiction and pain management. Yet, there are no highresolutionstructures of nAChR, thus making it a difficult pharmacological target. There existseveral resolved structures of the acetylcholine binding protein (AChBP), which is an aqueous protein that mimics the binding and activity of the extra-cellular domain in nAChR. Thus, weintend to use AChBP as the target, to identify new small-molecule ligands that could becomepotential pharmaceuticals against nAChR. Such ligands may also help distinguish between thechemical features of AChBP and the various subtypes of nAChR.