FIGURE 3.

Three-dimensional structure of VvPL2. A, schematic model of VvPL2 color-ramped blue (N terminus) to red (C terminus) and with its catalytic metal modeled as a Mn²⁺ shown as a purple sphere. B, superimposition of GalA from the +1 site of the YePL2A complex (Protein Data Bank entry 2V8K) within the active center of VvPL2. The backbone of VvPL2 is shown as a gray schematic with the metal-binding residues displayed as gray sticks, ordered waters as red spheres, Mn²⁺ as a purple sphere, and the stabilizing residue (Arg-304) and Brønstead base (Arg-191) as cyan sticks. The distances between the 2-OH and 3-OH of GalA and Arg-304, C5 and Arg-191, and the Mn²⁺ ion and the uronate group oxygens are labeled and shown as red dashes. C, the metal binding pocket of VvPL2 with N-terminal His tag. The map of the active center residues coordinating the transition metal is presented as maximum likelihood/σ_A weighted 2F_o −F_c densities, contoured at 1.0 σ and carved at 1.5 Å. The coordinated Mn²⁺ and ordered water are displayed as silver and red spheres, respectively. The presence of two tartrate molecules within the N-terminal His tag complex are rendered as yellow ball-and-stick models. D, alignment of the YePL2A (Protein Data Bank entry 2V8J; gray) and VvPL2 (green) metal coordination pocket. Residues are modeled as sticks, Mn²⁺ as purple spheres, and waters as red spheres. Residues are labeled using VvPL2/YePL2A numbering. Bond distances are indicated with yellow dashed lines. Consurf mapping displaying the conserved (magenta) and divergent (cyan) surface features of VvPL2 with subfamily 1 (E) and subfamily 2 (F) members. The highly conserved residues (Lys-152, Arg-191, Arg-304, and metal pocket) and location of the lysine-tryptophan site (K300W) are labeled.