title: Tandem mass spectrometry and nuclear magnetic resonance spectroscopy studies of Candida bombicola sophorolipids and product formed on hydrolysis by cutinase.
abstract: Natural mixtures of sophorolipids produced by the yeast Candida bombicola have been analyzed by fast atom bombardment (FAB)-MS and collision-induced dissociation (CID)-MS. Some pure components have been analysed by two-dimensional NMR spectroscopy. The presence of acidic, lactonic, and O-acetylated forms and the position of double bonds in the fatty acid part of these glycolipids can be easily inferred from positive and negative ion FAB-mass spectra. Details about position of O-acetylation can be obtained from CID mass spectra of [M+H]+ and [M-H]- ions and from the NMR spectra. Differences in CID fragmentation between protonated and sodiated molecular ions are discussed in detail. Enzymatic hydrolysis of 6',6"-di-O-acetyl sophorolipid lactone by cutinase from Fusarium solani results specifically in the removal of the 6'-O-acetyl group, whereas the 6"-O-acetyl and lactone group are resistant. This specificity is explained from a three-dimensional model of the sophorolipid generated on the basis of the short 1H,1H distances as inferred from the NMR (ROESY) spectra.
authors.affiliation: Bijvoet Center for Biomolecular Research, Mass Spectrometry Group, University of Utrecht, The Netherlands.
authors.forename: C G
authors.initials: CG
authors.lastname: de Koster
authors.forename: W
authors.initials: W
authors.lastname: Heerma
authors.forename: H A
authors.initials: HA
authors.lastname: Pepermans
authors.forename: A
authors.initials: A
authors.lastname: Groenewegen
authors.forename: H
authors.initials: H
authors.lastname: Peters
authors.forename: J
authors.initials: J
authors.lastname: Haverkamp
mesh_terms: D000838:Anions; D002175:Candida / Q000378:metabolism*; D002240:Carbohydrate Sequence; D002265:Carboxylic Ester Hydrolases; D003902:Detergents; D006017:Glycolipids / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013501:Surface-Active Agents / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D000838:Anions; D003902:Detergents; D006017:Glycolipids; D013501:Surface-Active Agents; D002265:Carboxylic Ester Hydrolases; C019952:cutinase