Details

Autor(en) / Beteiligte

• Lebeer, Sarah
• Verhoeven, Tine L.A
• Francius, Grégory
• Schoofs, Geert
• Lambrichts, Ivo
• Dufrêne, Yves
• Vanderleyden, Jos
• De Keersmaecker, Sigrid C.J

Titel

Identification of a Gene Cluster for the Biosynthesis of a Long, Galactose-Rich Exopolysaccharide in Lactobacillus rhamnosus GG and Functional Analysis of the Priming Glycosyltransferase

Ist Teil von

• Applied and Environmental Microbiology, 2009-06, Vol.75 (11), p.3554-3563

Ort / Verlag

Washington, DC: American Society for Microbiology

Erscheinungsjahr

2009

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Cell surface polysaccharides have an established role as virulence factors in human bacterial pathogens. Less documented are the biosynthesis and biological functions of surface polysaccharides in beneficial bacteria. We identified a gene cluster that encodes the enzymes and regulatory and transporter proteins for the different steps in the biosynthesis of extracellular polysaccharides (EPS) of the well-documented probiotic strain Lactobacillus rhamnosus GG. Subsequent mutation of the welE gene, encoding the priming glycosyltransferase within this cluster, and comparative phenotypic analyses of wild-type versus mutant strains confirmed the specific function of this gene cluster in the biosynthesis of high-molecular-weight, galactose-rich heteropolymeric EPS molecules. The phenotypic analyses included monomer composition determination, estimation of the polymer length of the isolated EPS molecules, and single-molecule force spectroscopy of the surface polysaccharides. Further characterization of the welE mutant also showed that deprivation of these long, galactose-rich EPS molecules results in an increased adherence and biofilm formation capacity of L. rhamnosus GG, possibly because of less shielding of adhesins such as fimbria-like structures.