FIGURE 1.

Overall structure of hUGDH bound with UDP-Glc and NADH. A, protein subunit with α-helices and β-strands numbered in red and yellow, respectively. The central interdomain α10 helix is shown in cyan. B, structural superimposition of the subunits of hUGDH (PDB code 2Q3E) (blue) and SpUGDH (PDB code 1DLJ) (orange). The flexible C-terminal region of SpUGDH is shown in red. C, assembly of hUGDH subunits into dimers. Regions forming dimer contacts are shown in blue and yellow. Arg²⁶⁰, which extends into the adjacent substrate binding pocket, is shown in red. D, formation of the functional hUGDH hexamer.