FIGURE 1.

Structure of the DsrAB sulfite reductase bound to DsrC. A, secondary structure representation of the α₂β₂γ₂ assembly (DsrAB sulfite reductase bound to DsrC), with the cofactors in ball-and-stick mode. DsrA (chains A and D) is colored blue, DsrB (chains B and E) is magenta, and DsrC (chains C and F) is green. The distance between the cofactors from one αβγ unit is displayed on the right side. Color code is yellow, carbon; red, oxygen; blue, nitrogen; brown, iron; and green, sulfur. B, molecular surface of theα₂β₂γ₂ assembly with oneαβγ unit in gray and the other colored according to A. C, superposition of DsrA and DsrB. N-term, N terminus; C-term, C terminus.