Malonate: a versatile cryoprotectant and stabilizing solution for salt-grown macromolecular crystals

Collection of quality data on high-energy synchrotron sources requires the selection of a cryoprotectant that allows protein crystals to be cryocooled without damage to the crystal and with suppression of ice formation. The use of sodium malonate as a versatile cryoprotectant for salt-grown protein crystals is presented here. In addition to its useful cryoprotectant properties, sodium malonate can also function as a versatile stabilizing solution that allows the manipulation, derivatization and ligand soaking of crystals grown from salt that may not be possible in the crystal mother liquor.