Flexibility of truncated and full-length glucansucrase GTF180 enzymes from Lactobacillus reuteri 180.

The FEBS journal

PubMedID: 24597929

Pijning T, Vujicic-┼Żagar A, Kralj S, Dijkhuizen L, Dijkstra BW. Flexibility of truncated and full-length glucansucrase GTF180 enzymes from Lactobacillus reuteri 180. FEBS J. 2014;.
Glucansucrase enzymes synthesize high-molecular-mass extracellular a-glucan polysaccharides from sucrose. Previously, the crystal structure of truncated glucansucrase GTF180-?N from Lactobacillus reuteri 180 (lacking the N-terminal domain) revealed an elongated overall structure with two remote domains (IV and V) extending away from the core. In contrast, a new crystal form of the a-1,6/a-1,3 specific glucansucrase GTF180-?N shows a ~120(o) rotation of domain V about a hinge located between domains IV and V, giving a much more compact structure than before. Positional variability of domain V in solution is confirmed by small angle X-ray scattering (SAXS) experiments and rigid-body ensemble calculations. In addition, SAXS measurements of full-length GTF180 also provide the first structural data for a full-length glucansucrase, showing that the enzyme has an almost symmetric boomerang-like molecular shape with a bend likely located between domains IV and V. The ~700-residue N-terminal domain, which is not present in the crystal structures, extends away from domain V and the catalytic core of the enzyme. We conclude that, due to the hinge region, in solution GTF180-?N (and likely also the full-length GTF180) shows conformational flexibility; this may be a general feature of GH70 glucansucrases. This article is protected by copyright. All rights reserved.