title: Structural and biophysical properties of a synthetic channel-forming peptide: designing a clinically relevant anion selective pore.
abstract: The design, synthesis, modeling and in vitro testing of channel-forming peptides derived from the cys-loop superfamily of ligand-gated ion channels are part of an ongoing research focus. Over 300 different sequences have been prepared based on the M2 transmembrane segment of the spinal cord glycine receptor α-subunit. A number of these sequences are water-soluble monomers that readily insert into biological membranes where they undergo supramolecular assembly, yielding channels with a range of selectivities and conductances. Selection of a sequence for further modifications to yield an optimal lead compound came down to a few key biophysical properties: low solution concentrations that yield channel activity, greater ensemble conductance, and enhanced ion selectivity. The sequence NK(4)-M2GlyR T19R, S22W (KKKKPARVGLGITTVLTMRTQW) addressed these criteria. The structure of this peptide has been analyzed by solution NMR as a monomer in detergent micelles, simulated as five-helix bundles in a membrane environment, modified by cysteine-scanning and studied for insertion efficiency in liposomes of selected lipid compositions. Taken together, these results define the structural and key biophysical properties of this sequence in a membrane. This model provides an initial scaffold from which rational substitutions can be proposed and tested to modulate anion selectivity. This article is part of a Special Issue entitled: Protein Folding in Membranes.
authors.affiliation: Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: U
authors.initials: U
authors.lastname: Bukovnik
authors.forename: J
authors.initials: J
authors.lastname: Gao
authors.forename: G A
authors.initials: GA
authors.lastname: Cook
authors.forename: L P
authors.initials: LP
authors.lastname: Shank
authors.forename: M B
authors.initials: MB
authors.lastname: Seabra
authors.forename: B D
authors.initials: BD
authors.lastname: Schultz
authors.forename: T
authors.initials: T
authors.lastname: Iwamoto
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: J M
authors.initials: JM
authors.lastname: Tomich
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000838:Anions; D055592:Biophysical Phenomena; D002942:Circular Dichroism; D003198:Computer Simulation; D003545:Cysteine / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D061985:Madin Darby Canine Kidney Cells; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D018009:Receptors, Glycine / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012996:Solutions; D053835:Unilamellar Liposomes / Q000737:chemistry
chemical_list: D000838:Anions; D008055:Lipids; D008823:Micelles; D010455:Peptides; D018009:Receptors, Glycine; D012996:Solutions; D053835:Unilamellar Liposomes; D012967:Sodium Dodecyl Sulfate; D003545:Cysteine