title: Deciphering the late steps in the biosynthesis of the anti-tumour indolocarbazole staurosporine: sugar donor substrate flexibility of the StaG glycosyltransferase.
abstract: The indolocarbazole staurosporine is a potent inhibitor of a variety of protein kinases. It contains a sugar moiety attached through C-N linkages to both indole nitrogen atoms of the indolocarbazole core. Staurosporine biosynthesis was reconstituted in vivo in a heterologous host Streptomyces albus by using two different plasmids: the 'aglycone vector' expressing a set of genes involved in indolocarbazole biosynthesis together with staG (encoding a glycosyltransferase) and/or staN (coding for a P450 oxygenase), and the 'sugar vector' expressing a set of genes responsible for the biosynthesis of the sugar moiety. Attachment of the sugar to the two indole nitrogens of the indolocarbazole core was dependent on the combined action of StaG and StaN. When StaN was absent, the sugar was attached only to one of the nitrogen atoms, through an N-glycosidic linkage, as in the indolocarbazole rebeccamycin. The StaG glycosyltransferase showed flexibility with respect to the sugar donor. When the 'sugar vector' was substituted by constructs directing the biosynthesis of l-rhamnose, L-digitoxose, L-olivose and D-olivose, respectively, StaG and StaN were able to transfer and attach all of these sugars to the indolocarbazole aglycone.
authors.affiliation: Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain.
authors.forename: Aaroa P
authors.initials: AP
authors.lastname: Salas
authors.forename: Lili
authors.initials: L
authors.lastname: Zhu
authors.forename: César
authors.initials: C
authors.lastname: Sánchez
authors.forename: Alfredo F
authors.initials: AF
authors.lastname: Braña
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rohr
authors.forename: Carmen
authors.initials: C
authors.lastname: Méndez
authors.forename: José A
authors.initials: JA
authors.lastname: Salas
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002227:Carbazoles / Q000378:metabolism; D003001:Cloning, Molecular; D003837:Deoxy Sugars / Q000378:metabolism; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism*; D006601:Hexoses / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D012210:Rhamnose / Q000378:metabolism; D019311:Staurosporine / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002227:Carbazoles; D003837:Deoxy Sugars; D006601:Hexoses; D007211:Indoles; C407877:olivose; C030374:indole; C020615:digitoxose; D009251:NADPH-Ferrihemoprotein Reductase; D016695:Glycosyltransferases; D019311:Staurosporine; D012210:Rhamnose