the present invention relates to a method for preparing a solution of a refolded , recombinantly expressed or chemically synthesized eukaryotic membrane protein in monodisperse form , to methods for preparing a crystalline form of a recombinantly expressed or chemically synthesized membrane protein , to a crystalline form of a recombinantly expressed , or chemically synthesized eukaryotic membrane protein , and to a crystalline form of a complex of a recombinantly expressed or chemically synthesized eukaryotic membrane protein and of an accessory agent .