Fig. 5. Active site residues of the apo-protomer liganded with sulfate at 1.95 Å (A), the binary enzyme product complex with APS at 2.6 Å (B), and the ternary product complex with an additional pyrophosphate at 2.8 Å (C). All atoms are shown with the final 2F_o – F_c electron density contoured at 1.0σ.