title: Simultaneous Determination of Absolute Configuration and Quantity of Lipopeptides Using Chiral Liquid Chromatography/Mass Spectrometry and Diastereomeric Internal Standards.
abstract: Lipopeptides promote innate immune response and are related to disease pathology. To investigate the newly emerging roles of lipopeptides, accurate measurements of stereoisomers with multiple chiral centers are essential yet challenging. This work uses (3R)- and (3S)-(15-methyl-3-((13-methyltetradecanoyl)oxy)hexadecanoyl)glycyl-l-serine, abbreviated as l-serine-(R+S)-Lipid 654, to develop a method that combines chiral liquid chromatography, a diastereomeric mixture of isotopically labeled internal standards, and multiple reaction monitoring mass spectrometry. The new method allows for simultaneously determining the absolute configuration and quantity of stereoisomers of bacteria-derived lipopeptides. Total lipid extracts of nine evaluated bacteria strains had different amounts, but only the (R)-isoform of l-serine-Lipid 654. The developed method also allowed for the first quantitative analysis of hydrolysis of a nonphospholipid as a novel substrate of honey bee venom phospholipase A2.
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
authors.forename: Reza
authors.initials: R
authors.lastname: Nemati
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
authors.forename: Christopher
authors.initials: C
authors.lastname: Dietz
authors.affiliation: Department of Immunology and Medicine, University of Connecticut School of Medicine , Farmington, Connecticut 06030, United States.
authors.forename: Emily
authors.initials: E
authors.lastname: Anstadt
authors.affiliation: Department of Immunology and Medicine, University of Connecticut School of Medicine , Farmington, Connecticut 06030, United States.
authors.forename: Robert
authors.initials: R
authors.lastname: Clark
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Smith
authors.affiliation: Department of Oral Health and Diagnostic Sciences, University of Connecticut School of Dental Medicine , Farmington, Connecticut 06030, United States.
authors.forename: Frank
authors.initials: F
authors.lastname: Nichols
authors.affiliation: Department of Chemistry, University of Connecticut , Storrs, Connecticut 06269-3060, United States.|Institute for Systems Genomics, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Xudong
authors.identifier: 0000-0001-9432-5065
authors.initials: X
authors.lastname: Yao
mesh_terms: D041963:Bacteroidetes / Q000737:chemistry; D002853:Chromatography, Liquid / Q000592:standards; D055666:Lipopeptides / Q000032:analysis* / Q000378:metabolism; D013058:Mass Spectrometry / Q000592:standards; D015394:Molecular Structure; D017861:Porphyromonas / Q000737:chemistry; D018713:Prevotella intermedia / Q000737:chemistry; D014208:Treponema / Q000737:chemistry
chemical_list: D055666:Lipopeptides