title: Secondary structure, stability and tetramerisation of recombinant K(V)1.1 potassium channel cytoplasmic N-terminal fragment.
abstract: The recombinant N-terminal fragment (amino acids 14-162) of a tetrameric voltage-gated potassium channel (K(V)1.1) has been studied using spectroscopic techniques. Evidence is presented that it forms a tetramer in aqueous solution, whereas when solubilised in 1% Triton X-100 it remains monomeric. The secondary structure content of both monomeric and tetrameric K(V)1.1 N-terminal fragment has been estimated from FTIR and CD spectroscopy to be 20-25% alpha-helix, 20-25% beta-sheet, 20% turns and 30-40% random coil. Solubilisation of the protein in detergent is shown by hydrogen-deuterium exchange analysis to alter tertiary structure rather than secondary structure and this may be the determining factor in tetramerisation ability. Using molecular modelling we propose a supersecondary structure consisting of two structural domains.
authors.affiliation: Department of Biochemistry and Molecular Biology, Royal Free Hospital School of Medicine, London, UK.
authors.forename: G W
authors.initials: GW
authors.lastname: Abbott
authors.forename: M
authors.initials: M
authors.lastname: Bloemendal
authors.forename: I H
authors.initials: IH
authors.lastname: Van Stokkum
authors.forename: E A
authors.initials: EA
authors.lastname: Mercer
authors.forename: R T
authors.initials: RT
authors.lastname: Miller
authors.forename: S
authors.initials: S
authors.lastname: Sewing
authors.forename: M
authors.initials: M
authors.lastname: Wolters
authors.forename: O
authors.initials: O
authors.lastname: Pongs
authors.forename: S K
authors.initials: SK
authors.lastname: Srai
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000737:chemistry; D051662:Kv1.1 Potassium Channel; D008969:Molecular Sequence Data; D017830:Octoxynol; D015221:Potassium Channels / Q000737:chemistry*; D024642:Potassium Channels, Voltage-Gated; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011994:Recombinant Proteins; D051662:Kv1.1 Potassium Channel; D017830:Octoxynol