title: Characterization of phthiocerol and phthiodiolone dimycocerosate esters of M. tuberculosis by multiple-stage linear ion-trap MS.
abstract: Both phthiocerol/phthiodiolone dimycocerosate (PDIM) and phenolic glycolipids are abundant virulent lipids in the cell wall of various pathogenic mycobacteria, which can synthesize a wide range of complex high-molecular-mass lipids. In this article, we describe linear ion-trap MS(n) mass spectrometric approach for structural study of PDIMs, which were desorbed as the [M + Li](+) and [M + NH(4)](+) ions by ESI. We also applied charge-switch strategy to convert the mycocerosic acid substituents to their N-(4-aminomethylphenyl) pyridinium (AMPP) derivatives and analyzed them as M (+) ions, following alkaline hydrolysis of the PDIM to release mycocerosic acids. The structural information from MS(n) on the [M + Li](+) and [M + NH(4)](+) molecular species and on the M (+) ions of the mycocerosic acid-AMPP derivative affords realization of the complex structures of PDIMs in Mycobacterium tuberculosis biofilm, differentiation of phthiocerol and phthiodiolone lipid families and complete structure identification, including the phthiocerol and phthiodiolone backbones, and the mycocerosic acid substituents, including the locations of their multiple methyl side chains, can be achieved.
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Kelly N
authors.initials: KN
authors.lastname: Flentie
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO.
authors.forename: Christina L
authors.initials: CL
authors.lastname: Stallings
authors.affiliation: Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid Research, Department of Internal Medicine.
authors.forename: John
authors.initials: J
authors.lastname: Turk
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen, Groningen, The Netherlands.
authors.forename: Adriaan J
authors.initials: AJ
authors.lastname: Minnaard
authors.affiliation: Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid Research, Department of Internal Medicine, fhsu@im.wust.edu.
authors.forename: Fong-Fu
authors.initials: FF
authors.lastname: Hsu
mesh_terms: D018441:Biofilms; D004952:Esters / Q000032:analysis / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006017:Glycolipids / Q000737:chemistry; D008055:Lipids / Q000032:analysis / Q000737:chemistry*; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000502:physiology; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014376:Tuberculosis / Q000382:microbiology
chemical_list: D004952:Esters; D005227:Fatty Acids; D006017:Glycolipids; D008055:Lipids; C032992:mycocerosic acid; C008901:phthiocerol dimycocerosate
keywords: Mycobacterium tuberculosis; biofilm; electrospray ionization; glycolipid; higher collision energy dissociation; lipidomics; mass spectrometry; microbial lipid