Secondary structure, stability and tetramerisation of recombinant K(V)1.1 potassium channel cytoplasmic N-terminal fragment.
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.
Abbott
G W
GW
Department of Biochemistry and Molecular Biology, Royal Free Hospital School of Medicine, London, UK.
Bloemendal
M
M
Van Stokkum
I H
IH
Mercer
E A
EA
Miller
R T
RT
Sewing
S
S
Wolters
M
M
Pongs
O
O
Srai
S K
SK
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
D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011994:Recombinant Proteins; D051662:Kv1.1 Potassium Channel; D017830:Octoxynol