Fig. 3.

Packing differences between V119 and I119 are translated to the SAM-binding site. Residue 119 is located in α5 and forms hydrophobic contacts with V115, R123, L130, V135 and L137. The larger Ile packs more tightly within the site, affecting the orientation of β5, which has an active-site residue (D141) on its distal end, and loosening up the SAM-biding site. Ribbon structures of the polymorphic sites from the final ns of three independent simulations of 119V and 119I PIMT are overlaid. Residue 119 is shown in space-filling representation and colored in red. The side chains of residues that interact with residue 119 are shown in stick representation and colored by atom type. SAM-binding residues are colored in green (D109), orange (H110), cyan (L114) and blue (D141) to match Fig. 4. A color version of this figure is available as supplementary data at PEDS online.