This is a the same protein as Puzzle 640 (Frizzled with a wider pocket than Puzzle 659) but this time the helix is unlocked. You can mutate any residue on the helix but none on Frizzled. We still have the new "Residue Interaction Energy" filter. Natural proteins avoid putting Tryptophan, Phenylalanine, and Tyrosine on the surface. However, Foldit often gives a score bonus if you load up the surface of your design with Tryptophan. The ResidueIE filter helps to counteract that, helping you make more useful designs. More details in the puzzle comments.