Fig. 3: Active site of RmlT.

a Cartoon representation of the active-site region of RmlT with TDP-rhamnose and interacting residues represented as sticks (PDB code: 8BZ7, chain D). Glycerol molecule used as cryo-protectant was found interacting with D198, likely mimicking a ribitol molecule. Water molecules and Mg²⁺ are shown as red and purple spheres, respectively. Hydrogen bonds and metal coordination are shown as black or light purple dashed lines. b Superposed active-sites (through residues 110–114) of RmlT/TDP-rhamnose copies (chains A–F) present in the asymmetric unit, coloured in different shades of wheat (PDB code: 8BZ7). TDP-rhamnose and some substrate-interacting residues are shown as sticks. RMSD relative to chain D: 0.034 Å (chain A), 0.046 Å (chain B), 0.027 Å (chain C), 0.042 Å (chain E) and 0.060 Å (chain F). c Cartoon representation of the active-site region of the apo RmlT (chain A) with donor substrate interaction residues represented as sticks (PDB code: 8BZ4). d Superposed active-sites (through residues 110–114) of apo RmlT copies present in the asymmetric unit of two different crystal forms, coloured in different shades of blue (PDB codes: 8BZ4 and 8BZ5). RMSD relative to chain A of 8BZ4: 0.966 Å (8BZ4 chain B), 0.319 Å (8BZ5 chain A), 0.229 Å (8BZ5 chain B), 0.070 Å (8BZ5 chain C) and 0.807 Å (8BZ5 chain D). Some substrate-interacting residues are represented as sticks with W89 in yellow. Loops A and B and helices h1, h4 and h13 are indicated. Positional variability of h1 and h4 is represented by arrows.