Structural highlights
Publication Abstract from PubMedGlucansucrase enzymes synthesize high-molecular-mass extracellular alpha-glucan polysaccharides from sucrose. Previously, the crystal structure of truncated glucansucrase glucosyltransferase (GTF)180-DeltaN 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. By contrast, a new crystal form of the alpha-1,6/alpha-1,3 specific glucansucrase GTF180-DeltaN shows an approximate 120o 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 experiments and rigid-body ensemble calculations. In addition, small angle X-ray scattering 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, as a result of the hinge region, in solution, GTF180-DeltaN (and likely also the full-length GTF180) shows conformational flexibility; this may be a general feature of GH70 glucansucrases. DATABASE: * Structural data for GTF180-DeltaN II have been deposited in the Protein Data Bank under accession code 4AYG. Flexibility of truncated and full-length glucansucrase GTF180 enzymes from Lactobacillus reuteri 180.,Pijning T, Vujicic-Zagar A, Kralj S, Dijkhuizen L, Dijkstra BW FEBS J. 2014 Mar 6. doi: 10.1111/febs.12769. PMID:24597929[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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