title: New aminocoumarin antibiotics formed by a combined mutational and chemoenzymatic approach utilizing the carbamoyltransferase NovN.
abstract: Five new aminocoumarin antibiotics were produced by a combined mutational and chemoenzymatic approach. For this purpose, the 3"-carbamoyltransferase NovN from the novobiocin producer Streptomyces spheroides was overexpressed in the heterologous host S. lividans as an N-terminal His(6) fusion protein and purified by nickel affinity chromatography. Five different 3"-unsubstituted aminocoumarin derivatives were isolated from mutants of the clorobiocin producer S. roseochromogenes, carrying single or multiple gene defects. All five compounds were readily accepted as substrates by NovN, and the 3"-carbamoylated products were isolated on a preparative scale. Their structures were elucidated by (1)H-NMR and mass spectroscopy, and their inhibitory activity on gyrase in vitro as well as their antibacterial activity was determined. The results give further insight into the structure-activity relationships of aminocoumarin antibiotics.
authors.affiliation: Pharmazeutische Biologie, Pharmazeutisches Institut, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 8, 72076 Tuebingen, Germany.
authors.forename: Hui
authors.initials: H
authors.lastname: Xu
authors.forename: Lutz
authors.initials: L
authors.lastname: Heide
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: Li
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology; D001483:Base Sequence; D002219:Carbamates / Q000378:metabolism; D019878:Carboxyl and Carbamoyl Transferases / Q000378:metabolism*; D003374:Coumarins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009154:Mutation; D009675:Novobiocin / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D059005:Topoisomerase II Inhibitors
chemical_list: D000900:Anti-Bacterial Agents; D002219:Carbamates; D003374:Coumarins; D011993:Recombinant Fusion Proteins; D059005:Topoisomerase II Inhibitors; D009675:Novobiocin; D019878:Carboxyl and Carbamoyl Transferases