title: Rhizobium meliloti lacking mosA synthesizes the rhizopine scyllo-inosamine in place of 3-O-methyl-scyllo-inosamine.
abstract: The Rhizobium meliloti Rm220-3 mos locus producing the rhizopine scyllo-inosamine (SI) in nodules is shown to consist of three ORFs (ORF1, mosB and mosC) arranged in an operon structure. This differs from the R. meliloti L5-30 mos locus, which produces 3-O-methyl-scyllo-inosamine (3-O-MSI), by the complete absence of mosA. The deletion covers a region of 1235 nt and includes the entire mosA gene as well as the sequence both upstream and downstream. As a result, Rm220-3 mos ORF1 shares a 5' region common with L5-30 ORF1 but includes an additional 10 bp insertion and a section in the L5-30 mosA and mosB intercistronic region. Antibodies against L5-30 Mos proteins detected MosB and MosC proteins in Rm220-3-induced nodules but no translation product for either ORF1 or mosA was detected. A construct prepared from the L5-30 mos locus which has a truncated mosA gene produces SI rather than 3-O-MSI, confirming this gene is involved in a methylation step in the production of 3-O-MSI. Further, changes made to this ORF result in reduced levels of the rhizopine.
authors.affiliation: Department of Crop Protection, Waite Agricultural Research Institute, University of Adelaide, Australia.
authors.forename: J P
authors.initials: JP
authors.lastname: Rao
authors.forename: W
authors.initials: W
authors.lastname: Grzemski
authors.forename: P J
authors.initials: PJ
authors.lastname: Murphy
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D001483:Base Sequence; D015153:Blotting, Western; D002876:Chromosomes, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D004590:Electrophoresis, Paper; D017353:Gene Deletion; D007294:Inositol / Q000031:analogs & derivatives* / Q000032:analysis / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D000455:Medicago sativa / Q000378:metabolism / Q000382:microbiology; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics; D015183:Restriction Mapping; D016415:Sequence Alignment; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000378:metabolism*; D013559:Symbiosis
chemical_list: D001426:Bacterial Proteins; C082577:rhizopine; D007294:Inositol