Fig. 1.

Overview of the ArrAB heterodimer from Shewanella sp. ANA-3. (A) View of the ArrA (yellow) and ArrB (blue) subunits with cofactors highlighted. The [4Fe–4S] clusters (FS0–FS4) and Mo atom are shown as spheres (Fe in orange, S in yellow, and Mo in purple). The PGD cofactors are shown in red labeled Q and P according to the DMSO reductase nomenclature. (B) Close-up view of the Mo-binding site in ArrA, focusing on the coordination of Mo (purple sphere) by water (red sphere), Cys193, and two PGD cofactors (C in gray, N in blue, O in red, S in yellow, and P in orange). Dashed lines illustrate coordination or hydrogen bonding.