title: Probing the substrate specificity of an enzyme catalyzing inactivation of streptogramin B antibiotics using LC-MS and LC-MS/MS.
abstract: LC-MS and LC-MS/MS analyses indicated that an enzyme responsible for inactivating the antibiotic etamycin is specific for streptogramins and acts on both type B-I and B-II streptogramin subgroups. No enzymatic activity was detected for other cyclodepsipeptides such as surfactins and viscosin. It was demonstrated using analogs of etamycin that the picolinyl moiety is essential to obtain enzyme-generated ring-opened compounds. Because the picolinyl moiety is also essential for the biological activity of streptogramins, it is proposed that this residue is a distinctive topographic feature in the binding of this group of antibiotics to enzyme active sites.
authors.affiliation: Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: K P
authors.initials: KP
authors.lastname: Bateman
authors.forename: P
authors.initials: P
authors.lastname: Thibault
authors.forename: K
authors.initials: K
authors.lastname: Yang
authors.forename: R L
authors.initials: RL
authors.lastname: White
authors.forename: L C
authors.initials: LC
authors.lastname: Vining
mesh_terms: D002853:Chromatography, Liquid; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity; D014769:Virginiamycin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014769:Virginiamycin