title: Shotgun Analysis of Rough-Type Lipopolysaccharides Using Ultraviolet Photodissociation Mass Spectrometry.
abstract: Detailed structural characterization of intact rough-type lipopolysaccharides (R-LPS) was accomplished using a multi-stage mass spectrometry (MS(3)) strategy consisting of collision-induced dissociation (CID) followed by 193 ultraviolet photodissociation (UVPD) implemented on an Orbitrap Fusion mass spectrometer. Complex mixtures of R-LPS from either Escherichia coli or Salmonella enterica were directly infused into the mass spectrometer using static source nanoelectrospray ionization (nanoESI). An initial CID event performed on an R-LPS precursor produced spectra with abundant ions corresponding to the lipid A and core oligosaccharide (OS) substructures. Comparison of CID spectra of R-LPS ions with varying lipid A and core OS structures verifies that lipid A and core OS ions are consistently produced in high abundance. The resulting lipid A and core OS ions were subsequently activated by CID, high-energy collision-induced dissociation (HCD), or UVPD. For both the lipid A and core OS substructures, HCD and UVPD produced highly informative complementary spectra, with UVPD of the core OS producing an extensive array of cross-ring cleavage fragments. Successful discernment of E. coli R-LPS structures with isomeric core structures confirmed the degree to which subtle structural differences could be determined using this method.
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Dustin R
authors.initials: DR
authors.lastname: Klein
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Dustin D
authors.initials: DD
authors.lastname: Holden
authors.affiliation: Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brodbelt
mesh_terms: D004926:Escherichia coli / Q000737:chemistry; D008070:Lipopolysaccharides / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*; D036103:Nanotechnology; D055668:Photochemical Processes; D019779:Salmonella enterica / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D008070:Lipopolysaccharides