Crystallization and preliminary X-ray diffraction studies of 6-phosphogluconate dehydrogenase from Lactococcus lactis

6-Phosphogluconate dehydrogenase is one of the seven enzymes involved in th e pentose phosphate pathway. Crystals of a mammalian and a protozoan enzyme have been obtained previously and structures determined. It is reported he re that a bacterial fi-phosphogluconate dehydrogenase, from Lactococcus lac tis, has been purified and used in crystallization trials. Large prisms sui table for a detailed structural analysis have been obtained and characteriz ed as orthorhombic, space group F222, with a = 70.4, b = 105.7, c = 474.6 A ngstrom. Diffraction has been observed to 2.2 Angstrom resolution using syn chrotron radiation. Structural analysis, in combination with ongoing bioche mical characterization, will assist the elucidation of the structure-activi ty relationships of this enzyme.