title: Characterization of a cyclic nucleotide-activated K(+) channel and its lipid environment by using solid-state NMR spectroscopy.
abstract: Voltage-gated ion channels are large tetrameric multidomain membrane proteins that play crucial roles in various cellular transduction pathways. Because of their large size and domain-related mobility, structural characterization has proved challenging. We analyzed high-resolution solid-state NMR data on different isotope-labeled protein constructs of a bacterial cyclic nucleotide-activated K(+) channel (MlCNG) in lipid bilayers. We could identify the different subdomains of the 4×355 residue protein, such as the voltage-sensing domain and the cyclic nucleotide binding domain. Comparison to ssNMR data obtained on isotope-labeled cell membranes suggests a tight association of negatively charged lipids to the channel. We detected spectroscopic polymorphism that extends beyond the ligand binding site, and the corresponding protein segments have been associated with mutant channel types in eukaryotic systems. These findings illustrate the potential of ssNMR for structural investigations on large membrane-embedded proteins, even in the presence of local disorder.
authors: NMR Spectroscopy, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht (The Netherlands).
authors: Abhishek
authors: A
authors: Cukkemane
authors: Marc
authors: M
authors: Baldus
mesh_terms: D001665:Binding Sites; D002247:Carbon Isotopes / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D009587:Nitrogen Isotopes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D009711:Nucleotides / Q000737:chemistry* / Q000378:metabolism; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D002247:Carbon Isotopes; D008051:Lipid Bilayers; D009587:Nitrogen Isotopes; D009711:Nucleotides; D015221:Potassium Channels; D011994:Recombinant Proteins
keywords: cyclic nucleotide-gated channels; cyclic nucleotides; ion channels; lipids; solid-state NMR spectroscopy