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Title
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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
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Author
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Abstract
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| 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. |
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Language
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English
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Source (journal)
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Applied and environmental microbiology. - Baltimore, Md
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Publication
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Baltimore, Md
:
2009
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ISSN
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0099-2240
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DOI
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10.1128/AEM.02919-08
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Volume/pages
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75
:11
(2009)
, p. 3554-3563
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ISI
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000266345800021
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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