Expression, crystallization and preliminary X-ray analysis of isomaltulose synthase (PalI) from Klebsiella sp. LX3

Isomaltulose synthase (PalI) catalyzes the hydrolysis of the α-1,2 bond between the glucose and fructose moieties of sucrose and the formation of α-1,6 and α-1,1 bonds between the two components to produce isomaltulose (α-D-glucosylpyranosyl-1,6-D-fructofranose) and trehalulose (α-D-glucosylpyranosyl-1,1-D-fructofranose), respectively. The PalI protein has been overexpressed, purified and crystallized at 295 K using the hanging-drop vapour-diffusion method. The crystals diffract to 2.2 Å resolution using synchrotron radiation and belong to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a = 59.239, b = 94.153, c = 111.294 Å.