Fig. 1.

Catalytic pocket of B. subtilis and B. megaterium levansucrases in their apo-form. Residues playing different roles in catalysis are displayed as lines. Residue numbers in B. megaterium (cyan, PDB 3om2/3om4) and B. subtilis (white, PDB 1oyg) are depicted in bold font and in brackets, respectively. Sucrose from B. subtilis PDB 1pt2 is shown to define the catalytic pocket. PDB 3om2 belongs to Bm-LS variant D257A, thus residue D257displayed in this figure corresponds to Bm-LS PDB 3om4. Orientation of S173 in 3om2 and 3om4 is shown as full and outlined sticks, respectively. This figure is available in black and white in print and in color at Glycobiology online.