Systematic fragmentation patterns of archaeal intact polar lipids by HPLC-ESI-IT-MS

Archaea are ubiquitous and abundant microorganisms on Earth that mediate key global biogeochemical cycles. The headgroup attached to the sn-1 position in the glycerol backbone and the ether-linked isoprenoid lipids are among the diagnostic traits that distinguish Archaea from Bacteria and Eukarya. Over the last 30 years, numerous archaeal lipids were purified and described in pure cultures. Coupled high performance liquid chromatography (HPLC) ion trap mass spectrometry (ITMS) now enables the detection and rapid identification of intact polar lipids in relatively small samples, revealing a wide range of archaeal lipids in natural environments. Although major structural groups have been identified, the lack of a systematic evaluation of MS/MS fragmentation patterns has hindered the characterization of several atypical components that are therefore considered as unknowns. Here, we examined mass spectra resulting from lipid analysis of natural microbial communities using HPLC/electrospray ionization (ESI)/ ITMSⁿ, and depicted the systematics in MS² fragmentation of intact archaeal lipids. This report will be particularly useful for biochemists and geochemists interested in a rapid and straightforward characterization of intact archaeal membrane lipids.