title: TDP-L-megosamine biosynthesis pathway elucidation and megalomicin a production in Escherichia coli.
abstract: In vivo reconstitution of the TDP-l-megosamine pathway from the megalomicin gene cluster of Micromonospora megalomicea was accomplished by the heterologous expression of its biosynthetic genes in Escherichia coli. Mass spectrometric analysis of the TDP-sugar intermediates produced from operons containing different sets of genes showed that the production of TDP-l-megosamine from TDP-4-keto-6-deoxy-d-glucose requires only five biosynthetic steps, catalyzed by MegBVI, MegDII, MegDIII, MegDIV, and MegDV. Bioconversion studies demonstrated that the sugar transferase MegDI, along with the helper protein MegDVI, catalyzes the transfer of l-megosamine to either erythromycin C or erythromycin D, suggesting two possible routes for the production of megalomicin A. Analysis in vivo of the hydroxylation step by MegK indicated that erythromycin C is the intermediate of megalomicin A biosynthesis.
authors.affiliation: Microbiology Division, IBR (Instituto de Biología Molecular y Celular de Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina.
authors.forename: Mariana
authors.initials: M
authors.lastname: Useglio
authors.forename: Salvador
authors.initials: S
authors.lastname: Peirú
authors.forename: Eduardo
authors.initials: E
authors.lastname: Rodríguez
authors.forename: Guillermo R
authors.initials: GR
authors.lastname: Labadie
authors.forename: John R
authors.initials: JR
authors.lastname: Carney
authors.forename: Hugo
authors.initials: H
authors.lastname: Gramajo
mesh_terms: D000617:Aminoglycosides / Q000096:biosynthesis* / Q000737:chemistry; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics*; D004917:Erythromycin / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D023061:Gene Order; D005947:Glucose / Q000031:analogs & derivatives / Q000378:metabolism; D008847:Micromonospora / Q000235:genetics*; D008954:Models, Biological; D015394:Molecular Structure; D005810:Multigene Family; D009876:Operon; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013942:Thymine Nucleotides / Q000378:metabolism
chemical_list: D000617:Aminoglycosides; D001426:Bacterial Proteins; D011994:Recombinant Proteins; D013942:Thymine Nucleotides; C112447:dTDP-6-deoxy-4-ketoglucose; C008343:megalomicin A; D004917:Erythromycin; D005947:Glucose