title: Synthesis of glycerophosphorylated cyclic beta-(1,2)-glucans by Rhizobium meliloti ndv mutants.
abstract: The periplasmic cyclic beta-(1,2)-glucans of Rhizobium spp. are believed to provide functions during hypoosmotic adaptation and legume nodulation. In Rhizobium meliloti, cyclic beta-(1,2)-glucans are synthesized at highest levels when cells are grown at low osmolarity, and a considerable fraction (> or = 35%) of these glucans may become substituted with phosphoglycerol moieties. Thus far, two chromosomally encoded proteins, NdvA and NdvB, have been shown to function during cyclic beta-(1,2)-glucan biosynthesis; however, the precise roles for these proteins remain unclear. In the present study, we show that R. meliloti mutants lacking up to one-third of the downstream region of ndvB synthesize cyclic beta-(1,2)-glucans similar to those produced by wild-type cells with respect to size and phosphoglycerol substituent profile. In contrast, no phosphoglycerol substituents were detected on the cyclic beta-(1,2)-glucans synthesized by an R. meliloti ndvA mutant.
authors.affiliation: Department of Food Science, Pennsylvania State University, University Park 16802.
authors.forename: M W
authors.initials: MW
authors.lastname: Breedveld
authors.forename: J S
authors.initials: JS
authors.lastname: Yoo
authors.forename: V N
authors.initials: VN
authors.lastname: Reinhold
authors.forename: K J
authors.initials: KJ
authors.lastname: Miller
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000838:Anions; D001426:Bacterial Proteins / Q000235:genetics*; D005288:Ferredoxins / Q000235:genetics; D005936:Glucans / Q000096:biosynthesis*; D005994:Glycerophosphates / Q000096:biosynthesis*; D009682:Magnetic Resonance Spectroscopy; D009154:Mutation; D012231:Rhizobium; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D016339:Spectrometry, Mass, Fast Atom Bombardment; D047071:beta-Glucans
chemical_list: C081714:2Fe-2S ferredoxin; D018528:ATP-Binding Cassette Transporters; D000838:Anions; D001426:Bacterial Proteins; D005288:Ferredoxins; D005936:Glucans; D005994:Glycerophosphates; D047071:beta-Glucans; C056783:ndvA protein, Rhizobium meliloti; C080135:cyclic beta(1-2)glucan