Determination of fatty acid positions in native lipid A by positive and negative electrospray ionization mass spectrometry.
Lipid A is the endotoxic principle of the lipopolysaccharide fraction from Gram-negative bacteria. It is involved in the elicitation of cytokine production that leads to massive inflammation and to septic shock as a lethal consequence. For this reason, the structural elucidation of lipopolysaccharides from toxic Gram-negative bacteria is an important and complicated task, mainly owing to its natural heterogeneity. Here, a new methodology to infer the distribution of the primary and secondary acyl residues is described, based on electrospray ionization mass spectrometry (ESI-MS) of intact lipid A under high cone voltage in order to achieve in-source fragmentation. Under these conditions, acyl fragmentation is induced and a different regioselective cleavage of secondary fatty acids is observed in positive and negative ESI-MS, allowing the rapid identification of the lipid A structure.
Sforza
Stefano
S
Dipartimento di Chimica Organica e Industriale, Università di Parma, Parco Area delle Scienze 17/a, I-43100 Parma, Italy.
Silipo
Alba
A
Molinaro
Antonio
A
Marchelli
Rosangela
R
Parrilli
Michelangelo
M
Lanzetta
Rosa
R
D019117:Burkholderia / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry; D005227:Fatty Acids / Q000032:analysis*; D041121:Klebsiella oxytoca / Q000737:chemistry; D008050:Lipid A / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D005227:Fatty Acids; D008050:Lipid A