Structure of the α-1,6/α-1,4-specific glucansucrase GTFA from Lactobacillus reuteri 121

Acta Cryst. (2012). F68, 1448-1454 (http://doi.org/jw4)

Crystal structure of GTFA-ΔN determined at 3.6 Å resolution.

Glucansucrases are bacterial enzymes that synthesize extracellular α-glucan polysaccharides from sucrose. We determined the first crystal structure of an α-1,6/α-1,4-specific glucansucrase, the fully active N-terminally truncated reuteransucrase GTFA-ΔN, using crystals with an unusually high solvent content of 85%. The GTFA-ΔN structure revealed differences when compared with other glucansucrases, notably in the region following the transition-state stabilizing residue. In accordance with the conclusions from earlier mutation studies on GTFA, residues in this region are likely to orient acceptor sugar molecules, thereby determining the product specificity of different glucansucrases.