AdoHcy binds the DENV3 MTase with a much weaker affinity than do AdoMet and SIN.

<p>(<b>A</b>) Dose response of inhibition of the [³H]-SAM-MTase complex formation by AdoMet (black), AdoHcy (red), and SIN (green). The biotinylated DENV3 MTase and ³H-labeled SAM were incubated with or without compounds AdoMet, AdoHcy, and SIN. A two-fold dilution series was shown for each compound. The reaction mixtures were mixed with the streptavidin-coated SPA beads and quantified using a Microbeta² scintillation counter. (<b>B</b>). Superposition of the crystal structures of the MTase-SIN complex (green) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0076900#B23" target="_blank">23</a>] and the MTase-SAH complex (yellow) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0076900#B19" target="_blank">19</a>]. SAH and SIN are shown in stick representation. Atomic color coding is as follows (unless otherwise specified): carbon in yellow/green, oxygen in red, nitrogen in blue, and sulfur in orange. Potential hydrogen bonds are depicted in red dashed lines.