Racemic macromolecules for use in X-ray crystallography.

The ability to chemically synthesize entire macromolecules has allowed the production of racemic mixtures of proteins and oligonucleotides. These racemic mixtures have been used to produce centrosymmetric crystals. Although only modest results have been obtained to date, this technology should be useful for the solution of structures of moderately sized macromolecules and for the generation of electron-density maps with low phase error and model bias.