Characterization of a covalently linked complex involving ferredoxin and ferredoxin: NADP reductase

Ferredoxin and the flavoprotein, ferredoxin: NADP reductase, have been covalently linked by incubation in the presence of a water soluble carbodiimide. The cross-linking reaction yields an adduct having a 1:1 stoichiometry. The adduct has depressed levels of diaphorase and NADPH oxidase activity and is inactive in reduction of cytochrome c using NADPH as an electron donor. Thus, although similar to an adduct described by Zanetti and coworkers J Biol Chem 259: 6153–6157 (1984)] in its stoichiometry, the adduct described herein has significantly different enzymatic properties. It is suggested that this may be a reflection of differences in the interaction between the two proteins resulting from differences in experimental conditions in which the two adducts were prepared.Abbreviations Fd ferredoxin - Fp ferredoxin: NADP reductase - Fd Fp covalently linked Fd-Fp adduct - Fd:Fp noncovalently linked complex between Fd and Fp - EDC 1-ethyl-3-(dimethylaminopropyl) carbodiimide - Tris tris-hydroxymethylaminomethane - MOPS 3-(N-morpholino)propane sulfonic acid - DCIP 2,6-dichloropenolindophenol