Investigating microbial lipopeptides with novel mass spectrometry tools

Lipopeptides (LPs) are produced by microorganisms and are composed by a hydrophilic peptide ring connected to a hydrophobic lipid tail. The remarkable diversity in the lipopeptide structure confers the LPs class a large range of biological properties.
In today’s approach for lipopeptide screening, newly Identified lipopeptides by in Silico or In Vivo methods are generally produced and purified before their characterization by HPLC-MS/MS.

If mass spectrometry has been used so far as a tool to confirm the mass of a compound, we will show in this thesis that there are many other MS based tools, from ion mobility to mass spectrometry imaging, capable of both lipopeptide screening and identification, even in challenging conditions such as natural environment mimicking conditions.

The first part of this thesis will focus on the development of mass spectrometry imaging tools by providing semi-targeted approaches for lipopeptide detection and localization, based on Kendrick mass defect. Mass shift associated with complex samples will also be discussed. The second part of this manuscript will highlight the benefit of mass spectrometry ion mobility for lipopeptide identification, and the possible structural information on lipopeptides that can be extracted from the ion mobility data.