Crystallization and preliminary diffraction studies of malate dehydrogenase from Streptomyces aureofaciens.

Purified malate dehydrogenase (MDH) of Streptomyces aureofaciens was crystallized either in the absence or in the presence of NADH or NADPH coenzymes by hanging-drop vapour-diffusion method. An X-ray study has shown, that MDH crystals belong to space group C222(1) with unit-cell parameters a = 53.2 A, b = 104.

The activities of the two thioredoxins from Streptomyces aureofaciens are not interchangeable.

The physico-chemical features of the NADPH-thioredoxin reductase (TRR) and two thioredoxins from Streptomyces aureofaciens (A14) are reported. The activity of pure S. aureofaciens thioredoxin reductase decreased drastically in the presence of NADPH or NADH while NADP(+), NAD(+), as well as S.