High-resolution mass spectrometry and hydrogen/deuterium exchange study of mitorubrin azaphilones and nitrogenized analogues.
Azaphilones represent numerous groups of wild fungal secondary metabolites that exhibit exceptional tendency to bind to nitrogen atoms in various molecules, especially those containing the amine group. Nitrogenized analogues of mitorubrin azaphilones, natural secondary metabolites of Hypoxylon fragiforme fungus, have been detected in the fungal methanol extract in very low concentrations. Positive electrospray ionization interfaced with high-resolution mass spectrometry was applied for confirmation of the elemental composition of protonated species. Collision-induced dissociation (CID) experiments have been performed, and fragmentation mechanisms have been proposed. Additional information regarding both secondary metabolite analogue families has been reached by application of gas-phase proton/deuterium (H/D) exchanges performed in the collision cell of a triple quadrupole mass spectrometer. An incomplete H/D exchange with one proton less than expected was observed for both protonated mitorubrin azaphilones and their nitrogenized analogues. By means of the density functional theory, an appropriate explanation of this behavior was provided, and it revealed some information concerning gas-phase H/D exchange mechanism and protonation sites.
Université Pierre et Marie Curie, Institut Parisien de Chimie Moléculaire, UMR 7201-FR2769, Case Courrière 45, Bâtiment F, 716, 4, place Jussieu, 75252, Paris CEDEX 05, France.
Ljubica
L
Svilar
Vesna
V
Stankov-Jovanovic
Denis
D
Lesage
Héloïse
H
Dossmann
Jean-Claude
JC
Tabet
D001565:Benzoates / Q000032:analysis / Q000737:chemistry*; D001578:Benzopyrans / Q000032:analysis / Q000737:chemistry*; D002853:Chromatography, Liquid; D041961:Deuterium Exchange Measurement / Q000379:methods*; D029964:Fagus / Q000382:microbiology; D005658:Fungi / Q000737:chemistry / Q000302:isolation & purification; D000432:Methanol / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D010860:Pigments, Biological / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013816:Thermodynamics
D001565:Benzoates; D001578:Benzopyrans; D010860:Pigments, Biological; C494154:azaphilone; C521221:mitorubrin; D009584:Nitrogen; D000432:Methanol