Overview of the design process. A de novo designed homodimer, with its two monomers colored in green and purple (A), is connected into a single chain (B), and docked in a C12 layer group symmetry with three parameters a, b, and θ (C), resulting in a 2D lattice (D). Intersubunit binding interfaces are designed with hydrogen bond networks to confer specificity, show here as an example between the green and blue building blocks (E). (F) A 1.74 Å resolution crystal structure of the design SC_2L4HC2_23 (PDB ID 6EGC, white) superimposed onto the design model (rainbow); the design model deviates from the crystal by 1.08 Å RMSD.