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Pantoea stewartii WceF is a glycan biofilm modifying enzyme with a bacteriophage tailspike-like fold

Item Type:Article
Title:Pantoea stewartii WceF is a glycan biofilm modifying enzyme with a bacteriophage tailspike-like fold
Creators Name:Irmscher, T. and Roske, Y. and Gayk, I. and Dunsing, V. and Chiantia, S. and Heinemann, U. and Barbirz, S.
Abstract:Pathogenic microorganisms often reside in glycan-based biofilms. Concentration and chain length distribution of these mostly anionic exopolysaccharides (EPS) determine the overall biophysical properties of a biofilm and result in a highly viscous environment. Bacterial communities regulate this biofilm state via intracellular small-molecule signaling to initiate EPS synthesis. Reorganization or degradation of this glycan matrix, however, requires the action of extracellular glycosidases. So far, these were mainly described for bacteriophages that must degrade biofilms for gaining access to host bacteria. The plant pathogen Pantoea stewartii (P. stewartii) encodes the protein WceF within its EPS synthesis cluster. WceF has homologs in various biofilm forming plant pathogens of the Erwinia family. In this work we show that WceF is a glycosidase active on stewartan, the main P. stewartii EPS biofilm component. WceF has remarkable structural similarity with bacteriophage tailspike proteins (TSPs). Crystal structure analysis showed a native trimer of right-handed parallel β-helices. Despite of its similar fold, WceF lacks the high stability found in bacteriophage TSPs. WceF is a stewartan hydrolase and produces oligosaccharides, corresponding to single stewartan repeat units. However, compared to a stewartan-specific glycan hydrolase of bacteriophage origin, WceF showed lectin-like autoagglutination with stewartan, resulting in notably slower EPS cleavage velocities. This emphasizes that the bacterial enzyme WceF has a role in P. stewartii biofilm glycan matrix reorganization clearly different from that of a bacteriophage exopolysaccharide depolymerase.
Keywords:Biofilm, Pantoea Stewartii, Bacterial Pathogenesis, Glycoside Hydrolase, Exopolysaccharide, Oligosaccharide, X-Ray Crystallography, Parallel beta-Helix, Bacteriophage Tailspike
Source:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology
Page Range:100286
Date:13 January 2021
Official Publication:https://doi.org/10.1016/j.jbc.2021.100286
PubMed:View item in PubMed

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