title: Probing the interaction of lipids with the non-annular binding sites of the potassium channel KcsA by magic-angle spinning NMR.
abstract: The activity of the potassium channel KcsA is tightly regulated through the interactions of anionic lipids with high-affinity non-annular lipid binding sites located at the interface between the channel's subunits. Here we present solid-state phosphorous NMR studies that resolve the negatively charged lipid phosphatidylglycerol within the non-annular lipid-binding site. Perturbations in chemical shift observed upon the binding of phosphatidylglycerol are indicative of the interaction of positively charged sidechains within the non-annular binding site and the negatively charged lipid headgroup. Site directed mutagenesis studies have attributed these charge interactions to R64 and R89. Functionally the removal of the positive charges from R64 and R89 appears to act synergistically to reduce the probability of channel opening.
authors.affiliation: School of Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, UK.
authors.forename: Phedra
authors.initials: P
authors.lastname: Marius
authors.forename: Maurits R R
authors.initials: MR
authors.lastname: de Planque
authors.forename: Philip T F
authors.initials: PT
authors.lastname: Williamson
mesh_terms: D001120:Arginine / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D003001:Cloning, Molecular; D004594:Electrophysiology; D004926:Escherichia coli; D015640:Ion Channel Gating; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008564:Membrane Potentials / Q000502:physiology; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010715:Phosphatidylglycerols / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D008051:Lipid Bilayers; D010715:Phosphatidylglycerols; D015221:Potassium Channels; D011994:Recombinant Proteins; C107790:prokaryotic potassium channel; D001120:Arginine; D011188:Potassium