Fig. 1.
The electron transfer pathway leading from the protein surface to the FAD cofactor buried within the protein. Shown are the relative positions of the FAD cofactor and the Trp-triad (WA, WB, WC) in AtCry [blue, PDB entry 1U3D (37)] and EcPL [red, PDB entry 1DNP (48)]. The proposed magnetically sensitive species comprises a radical derived from the FAD and one from the terminal tryptophan residue, WC (Trp-324 in AtCry; Trp306 in EcPL). The center-to-center distance between the tricyclic isoalloxazine ring system of FAD and the indole group of WC is 1.90 nm in AtCry (37).