Single-particle electron cryomicroscopy permits structural characterization of noncrystalline protein samples, but throughput is limited by problems associated with sample preparation and image processing. Three-dimensional density maps are reconstructed from high resolution but noisy images of individual molecules. We show that self-assembled DNA nanoaffinity templates can create dense, nonoverlapping arrays of protein molecules, greatly facilitating data collection. We demonstrate this technique using a G-protein-coupled membrane receptor, a soluble G-protein, and a signaling complex of both molecules.