title: Structure, chemistry, and biological activity of pseudophomins A and B, new cyclic lipodepsipeptides isolated from the biocontrol bacterium Pseudomonas fluorescens.
abstract: Pseudophomins A and B are cyclic lipodepsipeptides isolated from Pseudomonas fluorescens strain BRG100, a bacterium with potential application for biocontrol of plant pathogens and weeds. Their chemical structures were established by a combination of spectroscopic data, X-ray crystallography, and selective chemical degradation. This unique chemical degradation allowed the unambiguous determination of the absolute configuration of the amino acid residue Leu-1, due to gamma-lactam formation followed by selective cleavage of the adjacent N(8)-C(7) bond. To the best of our knowledge this is the first application of gamma-lactam formation to the determination of absolute configuration of an adjacent amino acid. Pseudophomin B showed higher antifungal activity against the phytopathogens Phoma lingam/Leptosphaeria maculans and Sclerotinia sclerotiorum than pseudophomin A, and is likely to be the main component responsible for the antifungal activity of EtOAc extracts of strain BRG100. By contrast, pseudophomin A showed stronger inhibition of green foxtail (Setaria viridis) root germination than pseudophomin B.
authors.affiliation: Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon SK, Canada S7N 5C9. soledade.pedras@usask.ca
authors.forename: M Soledade C
authors.initials: MS
authors.lastname: Pedras
authors.forename: Nargis
authors.initials: N
authors.lastname: Ismail
authors.forename: J Wilson
authors.initials: JW
authors.lastname: Quail
authors.forename: Susan M
authors.initials: SM
authors.lastname: Boyetchko
mesh_terms: D000528:Alternaria / Q000187:drug effects; D000935:Antifungal Agents / Q000737:chemistry* / Q000494:pharmacology; D001203:Ascomycota / Q000187:drug effects; D018360:Crystallography, X-Ray; D006540:Herbicides / Q000737:chemistry* / Q000494:pharmacology; D019906:Nuclear Magnetic Resonance, Biomolecular; D010456:Peptides, Cyclic / Q000737:chemistry* / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D011487:Protein Conformation; D011551:Pseudomonas fluorescens / Q000737:chemistry* / Q000145:classification; D012232:Rhizoctonia / Q000187:drug effects; D032983:Setaria Plant / Q000187:drug effects
chemical_list: D000935:Antifungal Agents; D006540:Herbicides; D010456:Peptides, Cyclic; C460380:pseudophomin A; C460381:pseudophomin B