title: Characterization of Lipid A Variants by Energy-Resolved Mass Spectrometry: Impact of Acyl Chains.
abstract: Lipid A molecules consist of a diglucosamine sugar core with a number of appended acyl chains that vary in their length and connectivity. Because of the challenging nature of characterizing these molecules and differentiating between isomeric species, an energy-resolved MS/MS strategy was undertaken to track the fragmentation trends and map genealogies of product ions originating from consecutive cleavages of acyl chains. Generalizations were developed based on the number and locations of the primary and secondary acyl chains as well as variations in preferential cleavages arising from the location of the phosphate groups. Secondary acyl chain cleavage occurs most readily for lipid A species at the 3' position, followed by primary acyl chain fragmentation at both the 3' and 3 positions. In the instances of bisphosphorylated lipid A variants, phosphate loss occurs readily in conjunction with the most favorable primary and secondary acyl chain cleavages. Graphical Abstract ᅟ.
authors.affiliation: Department of Chemistry, University of Texas, Austin, TX, 78712, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Crittenden
authors.affiliation: Department of Chemistry, University of Texas, Austin, TX, 78712, USA.
authors.forename: Lucas D
authors.initials: LD
authors.lastname: Akin
authors.affiliation: Department of Chemistry, University of Texas, Austin, TX, 78712, USA.
authors.forename: Lindsay J
authors.initials: LJ
authors.lastname: Morrison
authors.affiliation: Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA.
authors.forename: M Stephen
authors.initials: MS
authors.lastname: Trent
authors.affiliation: Department of Chemistry, University of Texas, Austin, TX, 78712, USA. jbrodbelt@cm.utexas.edu.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brodbelt
mesh_terms: D008050:Lipid A / Q000737:chemistry* / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry; D010766:Phosphorylation; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014466:Ultraviolet Rays
chemical_list: D008050:Lipid A; D010710:Phosphates
keywords: Acyl chain; Collisional activation; Lipid A; Tandem mass spectrometry