title: Interaction of the K+ channel KcsA with membrane phospholipids as studied by ESI mass spectrometry.
abstract: In this study we have used electrospray ionization mass spectrometry (ESI-MS) to investigate interactions between the bacterial K(+) channel KcsA and membrane phospholipids. KcsA was reconstituted into lipid vesicles of variable lipid composition. These vesicles were directly analyzed by ESI-MS or mixed with trifluoroethanol (TFE) before analysis. In the resulting mass spectra, non-covalent complexes of KcsA and phospholipids were observed with an interesting lipid specificity. The anionic phosphatidylglycerol (PG), and, to a lesser extent, the zwitterionic phosphatidylethanolamine (PE), which both are abundant bacterial lipids, were found to preferentially associate with KcsA as compared to the zwitterionic phosphatidylcholine (PC). These preferred interactions may reflect the differences in affinity of these phospholipids for KcsA in the membrane.
authors.affiliation: Department of Biochemistry of Membranes, Center for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, The Netherlands. j.a.a.demmers@chem.uu.nl
authors.forename: Jeroen A A
authors.initials: JA
authors.lastname: Demmers
authors.forename: Annemieke
authors.initials: A
authors.lastname: van Dalen
authors.forename: Ben
authors.initials: B
authors.lastname: de Kruijff
authors.forename: Albert J R
authors.initials: AJ
authors.lastname: Heck
authors.forename: J Antoinette
authors.initials: JA
authors.lastname: Killian
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism*; D015221:Potassium Channels / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001426:Bacterial Proteins; D008051:Lipid Bilayers; D010743:Phospholipids; D015221:Potassium Channels; C107790:prokaryotic potassium channel