CRYSTAL-STRUCTURE OF EUKARYOTIC E3, LIPOAMIDE DEHYDROGENASE FROM YEAST

The crystal structure of eucaryotic lipoamide dehydrogenase from yeast has been determined by an X-ray analysis at 2.7 (partially at 2.4) An gstrom resolution, The enzyme has two identical subunits related by a pseudo twofold symmetry. The tertiary structure is similar to those of other procaryotic enzymes, The active site, consisting of FAD, Cys44, and Cys49 from one subunit and His457' from the other subunit, is hig hly conserved, This enzyme is directly bound to the core protein E2 of the 2-oxoglutarate dehydrogenase complex, whereas it is bound to the pyruvate dehydrogenase complex through a protein X. The calculated ele ctrostatic potential suggests two characteristic regions for binding w ith these two proteins.