PROTEIN CRYSTALS

A method for producing an ordered protein lattice, the method comprising: (a) providing a first component comprising a subunit of a homooligomeric protein assembly fused to a first subunit of a heterooligomeric protein assembly, and a second component comprising a second subunit of the heterooligomeric protein assembly, wherein the homooligomeric protein assembly and the heterooligomeric protein assembly are each symmetrical in two or three dimensions and share a rotational symmetry axis of the same order; (b) mixing said first monomer and said second monomer to produce a mixture; and (c1) (i) heating the mixture to a temperature about 2° C. to about 10° C. below the visible dissociation temperature; (ii) cooling the mixture by about 10° C. to about 20° C.; and (iii) repeating steps (i) and (ii) at least 10 times; or (c2) (i) heating the mixture to a temperature about 2° C. to about 30° C. or more below the visible dissociation temperature; and (ii) holding the mixture at a temperature about 2° C. to about 30° C. or more below the melt temperature, thereby producing an ordered protein lattice.