title: Use of a halogenase of hormaomycin biosynthesis for formation of new clorobiocin analogues with 5-chloropyrrole moieties.
abstract: The depsipeptide antibiotic hormaomycin, which is produced by Streptomyces griseoflavus W-384, contains a 5-chloropyrrole moiety. In the producer strain we identified the gene hrmQ that shows sequence similarity to FADH(2)-dependent halogenases. This gene was cloned and heterologously expressed in Streptomyces roseochromogenes var. oscitans DS12.976, which is the producer of the aminocoumarin antibiotic clorobiocin, which contains a 5-methylpyrrole moiety. For the present experiment, we used a mutant of this strain in which the respective pyrrole-5-methyltransferase had been inactivated. Expression of the halogenase hrmQ in this mutant strain led to the formation of two new clorobiocin derivatives that carried a 5-chloropyrrole moiety. These compounds were isolated on a preparative scale, their structures were elucidated by (1)H NMR spectroscopy and mass spectrometry, and their antibacterial activity was determined. The substrate of HrmQ is likely to be a pyrrole-2-carboxyl-S-[acyl carrier protein] thioester. If this assumption is true, this study presents the first experiment in combinatorial biosynthesis that uses a halogenase that acts on an acyl carrier protein-bound substrate.
authors.affiliation: Pharmazeutische Biologie, Pharmazeutisches Institut, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany. heide@uni-tuebingen.de
authors.forename: Lutz
authors.initials: L
authors.lastname: Heide
authors.forename: Lucia
authors.initials: L
authors.lastname: Westrich
authors.forename: Christine
authors.initials: C
authors.lastname: Anderle
authors.forename: Bertolt
authors.initials: B
authors.lastname: Gust
authors.forename: Bernd
authors.initials: B
authors.lastname: Kammerer
authors.forename: Jörn
authors.initials: J
authors.lastname: Piel
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D003001:Cloning, Molecular; D047630:Depsipeptides / Q000096:biosynthesis*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009675:Novobiocin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D010088:Oxidoreductases / Q000378:metabolism*; D011758:Pyrroles / Q000737:chemistry*; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D010456:Peptides, Cyclic
chemical_list: D000900:Anti-Bacterial Agents; D047630:Depsipeptides; D009675:Novobiocin; D010088:Oxidoreductases; D011758:Pyrroles; C510371:hormaomycin; D010456:Peptides, Cyclic; C006260:clorobiocin