CRYSTALLIZATION OF CROSS-LINKED ADRENODOXIN ADRENODOXIN REDUCTASE COMPLEX

The two forms of adrenodoxin reductase from bovine adrenals as well as recombinant bovine adrenodoxin and adrenodoxin reductase expressed in E. coli were purified and biochemically characterized. The recombinan t reductase was shown to be expressed as a single polypeptide that dis plays a retention time on a DEAE-Fractogel column identical to that of the second form (F2) of the mitochondrial reductase. The two forms of reductase demonstrate similar adrenodoxin reductase activities in the two types of systems comprising either cytochrome c or cytochrome P-4 50(11 beta) as the terminal electron acceptor. Adrenodoxin was coupled to each of the two forms of reductase using 1-ethyl-3-(3-dimethylamin opropyl) carbodiimide. An effective two-step method for the purificati on of the heterologous cross-linked complexes is described. The first crystallization of the cross-linked bimolecular complex of adrenodoxin reductase and adrenodoxin is reported.