title: Molecular basis of L-rhamnose branch formation in streptococcal coaggregation receptor polysaccharides.
abstract: The presence of L-rhamnose (Rha) branches in the coaggregation receptor polysaccharides (RPS) of Streptococcus gordonii 38 and Streptococcus oralis J22 was eliminated by replacement of wefB with ermAM in these strains. The expression of this gene in S. oralis 34 did not, however, result in the addition of Rha branches to the linear RPS of this strain, which is identical to that produced by the wefB-deficient mutant of S. gordonii 38. This paradoxical finding was explained by a subtle difference in acceptor specificity of the galactose-1-phosphotransferases encoded by downstream wefC in S. gordonii 38 and wefH in S. oralis 34. These genes were distinguished by the unique ability of WefC to act on the branched acceptor formed by the action of WefB.
authors.affiliation: Oral Infection and Immnunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Building 30, 30 Convent Drive, Bethesda, MD 20892, USA.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Soumya
authors.initials: S
authors.lastname: Ganguly
authors.forename: C Allen
authors.initials: CA
authors.lastname: Bush
authors.forename: John O
authors.initials: JO
authors.lastname: Cisar
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000378:metabolism*; D012210:Rhamnose / Q000378:metabolism*; D013291:Streptococcus / Q000235:genetics / Q000502:physiology*
chemical_list: D011135:Polysaccharides, Bacterial; D012210:Rhamnose