Complete Structural Elucidation of Monophosphorylated Lipid A by CID Fragmentation of Protonated Molecule and Singly Charged Sodiated Adducts

• DOI: 10.1021/jasms.2c00269
• Publication Date: 2022-12-21T04:44:01Z
• Authors: Ibrahim Aissa; Ágnes Dörnyei; Viktor Sándor; Anikó Kilár
• Keywords: Fragmentation; Lipid A

Lipid A, the inflammatory portion of lipopolysaccharides (LPS, endotoxins), is main component outer membrane Gram-negative bacteria. Its bioactivity in humans and animals strictly related to its chemical structure. In present work, fragmentation patterns singly charged monosodium [M + Na]+ disodium - H 2Na]+ adducts, as well protonated form monophosphorylated lipid A species were investigated detail using positive-ion electrospray ionization-based tandem (MS/MS) multistage mass spectrometry (MSn) with low-energy collision-induced dissociation (CID). Several synthetic native samples included study. We found that pattern disodiated quite similar well-characterized deprotonated molecule (typically detected negative-ion mode), while monosodiated contains fragment ions those both molecules. summary, we propose a new approach based on regularities only positively precursor dissect location phosphate group fatty acid moieties A. Moreover, this study provides better understanding so-called "chimera spectra", which are commonly during containing C-1 C-4' positional isomers but rarely identified mode.