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Towards mapping electrostatic interactions between Kdo2-lipid A and cationic antimicrobial peptides via ultraviolet photodissociation mass spectrometry

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Abstract

Cationic antimicrobial peptides (CAMPs) have been known to act as multi-modal weapons against Gram-negative bacteria. As a new approach to investigate the nature of the interactions between CAMPs and the surfaces of bacteria, native mass spectrometry and two MS/MS strategies (ultraviolet photodissociation (UVPD) and higher energy collisional activation (HCD)) are used to examine formation and disassembly of saccharolipid·peptide complexes. Kdo2-lipid A (KLA) is used as a model saccharolipid to evaluate complexation with a series of cationic peptides (melittin and three analogs). Collisional activation of the KLA·peptide complexes results in the disruption of electrostatic interactions, resulting in apo-sequence ions with shifts in the distribution of ions compared to the fragmentation patterns of the apo-peptides. UVPD of the KLA·peptide complexes results in both apo- and holo-sequence ions of the peptides, the latter in which the KLA remains bound to the truncated peptide fragment despite cleavage of a covalent bond of the peptide backbone. Mapping both the N- and C-terminal holo-product ions gives insight into the peptide motifs (specifically an electropositive KRKR segment and a proline residue) that are responsible for mediating the electrostatic interactions between the cationic peptides and saccharolipid.

Graphical abstract: Towards mapping electrostatic interactions between Kdo2-lipid A and cationic antimicrobial peptides via ultraviolet photodissociation mass spectrometry

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Publication details

The article was received on 10 Apr 2018, accepted on 27 Jun 2018 and first published on 27 Jun 2018


Article type: Paper
DOI: 10.1039/C8AN00652K
Citation: Analyst, 2018, Advance Article
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    Towards mapping electrostatic interactions between Kdo2-lipid A and cationic antimicrobial peptides via ultraviolet photodissociation mass spectrometry

    C. M. Crittenden, L. J. Morrison, M. D. Fitzpatrick, A. P. Myers, E. T. Novelli, J. Rosenberg, L. D. Akin, V. Srinivasa, J. B. Shear and J. S. Brodbelt, Analyst, 2018, Advance Article , DOI: 10.1039/C8AN00652K

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