Lipid fingerprints of intact viruses by MALDI-TOF/mass spectrometry

A number of viruses contain lipid membranes, which are in close contact with capsid proteins and/or nucleic acids and have an important role in the viral infection process. In this study membrane lipids of intact viruses have been analysed by MALDI-TOF/MS with a novel methodology avoiding lipid extraction and separation steps. To validate the novel method, a wide screening of viral lipids has been performed analysing highly purified intact bacterial and archaeal viruses displaying different virion architectures. Lipid profiles reported here contain all lipids previously detected by mass spectrometry analyses of virus lipid extracts. Novel details on the membrane lipid composition of selected viruses have also been obtained. In addition we show that this technique allows the study of lipid distribution easily in subviral particles during virus fractionation. The possibility to reliably analyse minute amounts of intact viruses by mass spectrometry opens new perspectives in analytical and functional lipid studies on a wider range of viruses including pathogenic human ones, which are difficult to purify in large amounts.