Ferredoxin/ferredoxin–thioredoxin reductase complex: Complete NMR mapping of the interaction site on ferredoxin by gallium substitution

Abstract

The reduction of ferredoxin–thioredoxin reductase (FTR) by plant‐type ferredoxin plays an important role in redox regulation in plants and cyanobacteria. Nuclear magnetic resonance (NMR) was used to map the binding sites on Synechocystis ferredoxin for FTR. A gallium‐substituted structural analog of this [2Fe–2S] ferredoxin was obtained by reconstituting the apoprotein in a refolding buffer containing gallium. For the first time, the complete interaction interface of a [2Fe–2S] ferredoxin with a target enzyme has been mapped by NMR chemical shift perturbation with this diamagnetic structural analog.