Complex structures of ALSV MTase with SAM and SAH.

(A and D) An electrostatic-surface representation of ALSV MTase in the SAM-bound (A) and SAH-bound (D) forms. The SAM and SAH molecules are shown as yellow and green sticks, respectively. The SAM/SAH-binding pocket is indicated with black dotted rectangle. The bound SAM and SAH molecules, whose electron densities are contoured at 2.8 σ using the |Fo|-|Fc| map, are shown in the black rectangle. (B and E) A cartoon representation of ALSV MTase in the SAM-bound (B) and SAH-bound (E) forms. Those structural elements involved in the formation of the ligand-binding pocket are labeled. (C and F) Detailed interactions between ALSV MTase and SAM (C) or SAH (F). Dashed lines indicate hydrogen bonds. (G, H and I) Overview of the SAM-binding pocket in DENV3 MTase (based on PDB code: 5E9Q). (G) An electrostatic-surface representation of DENV3 MTase bound with SAM. The SAM molecule is shown as orange sticks. (H) A cartoon representation of DENV3 MTase bound with SAM. Those structural elements involved in the formation of the ligand-binding pocket are labeled. (I) Detailed interactions between DENV3 MTase and SAM. Dashed lines indicate hydrogen bonds. Those SAM-binding residues in DENV3 MTase that are equivalent to those responsible for ALSV-MTase/SAM interactions are shown as cyan sticks, while the other two residues in DENV3 MTase that form additional hydrogen bonds with SAM are highlighted and shown as gray sticks.