Fig. 1. Structure and function of ferredoxin–NADP⁺ reductase (FNR). (A) Cartoon diagram comparing the concept of the ‘electrochemical leaf’ with the biological leaf. (B) and (C) Show structure of FNR complexed with ferredoxin (pdb ; 1GAQ).1 The position of bound NADP⁺ was included within the same structure (Pymol) by aligning the ferredoxin : FNR complex (pdb ; 1GAQ) with the structure of FNR in complex with NADP⁺ (pdb ; 1GJR);4 the protein structure from pdb ; 1GJR was then deleted to leave only the NADP⁺ molecule in position within the ferredoxin : FNR complex. (B) Projection in which FNR is shown as a charge-smoothed surface (red and blue represent positive and negative charges, respectively) and bound ferredoxin is shown in green, as cartoon main chain. (C) Projection in which ferredoxin is shown as a charge-smoothed surface and FNR is shown as cartoon main chain in green. In both projections, FAD is represented as yellow sticks, and NADP⁺ is represented as mauve sticks.