title: Rhamnose biosynthesis in mycoplasmas requires precursor glycans larger than monosaccharide.
abstract: Despite the apparent absence of genes coding for the known pathways for biosynthesis, the monosaccharide rhamnose was detected in the d configuration in Mycoplasma pneumoniae and Mycoplasma pulmonis, and in both the d and l configurations in Mycoplasma arthritidis. Surprisingly, the monosaccharide glucose was not a precursor for rhamnose biosynthesis and was not incorporated at detectable levels in glucose-containing polysaccharides or glycoconjugates. In contrast, carbon atoms from starch, a polymer of glucose, were incorporated into rhamnose in each of the three species examined. When grown in a serum-free medium supplemented with starch, M. arthritidis synthesized higher levels of rhamnose, with a shift in the relative amounts of the d and l configurations. Our findings suggest the presence of a novel pathway for rhamnose synthesis that is widespread in the genus Mycoplasma.
authors.affiliation: Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Jordan
authors.forename: James M
authors.initials: JM
authors.lastname: Daubenspeck
authors.forename: Kevin
authors.initials: K
authors.lastname: Dybvig
mesh_terms: D009174:Mycoplasma / Q000378:metabolism*; D045645:Mycoplasma arthritidis / Q000378:metabolism*; D045803:Mycoplasma pulmonis / Q000378:metabolism*; D011019:Pneumonia, Mycoplasma / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D012210:Rhamnose / Q000096:biosynthesis*
chemical_list: D011134:Polysaccharides; D012210:Rhamnose