I did a quick little bit of searching and following back of citations, may have time to do so somewhere with easier access to paywalled journals tomorrow and if I misstated anything I will edit.

This protein SP1 (Stable Protein 1, originally from Aspen trees, a 12-part ring that is so stable it goes through boiling intact hence the name) forms hexagonal rings and as long as you don't mess with the parts that hold the hexagon together you an tack on interesting other things to the interior of the rings and the exterior. Keep hydrophobic patches around the exterior and you can get it to arrange itself into regular lattices. Keep the inside hydrophobic and you can get it to grab onto and encircle other hydrophobic particles of the proper size in solution.

Here they mixed the protein with protein-sized diamond particles, the rings grabbed those particles that were the proper size, and arranged themselves into flat extremely regular hexagonal arrays carrying the diamond particles along for the ride.