Homology models of the tetramerization domain of six eukaryotic voltage-gated potassium channels Kv1.1-Kv1.6.
The homology models of the tetramerization (T1) domain of six eukaryotic potassium channels, Kv1.1-Kv1.6, were constructed based on the crystal structure of the Shaker T1 domain. The results of amino acid sequence alignment indicate that the T1 domains of these K+ channels are highly conserved, with the similarities varying from 77% between Shaker and Kv1.6 to 93% between Kv1.2 and Kv1.3. The homology models reveal that the T1 domains of these Kv channels exhibit similar folds as those of Shaker K+ channel. These models also show that each T1 monomer consists of three distinct layers, with N-terminal layer 1 and C-terminal layer 3 facing the cytoplasm and the membrane, respectively. Layer 2 exhibits the highest structural conservation because it is located around the central hydrophobic core. For each Kv channel, four identical subunits assemble into the homotetramer architecture around a four-fold axis through the hydrogen bonds and salt bridges formed by 15 highly conserved polar residues. The narrowest opening of the pore is formed by the four conserved residues corresponding to R115 of the Shaker T1 domain. The homology models of these Kv T1 domains provide particularly attractive targets for further structure-based studies.
Liu
Hsuan-Liang
HL
Department of Chemical Engineering and Graduate Institute of Biotechnology, National Taipei University of Technology, No. 1 Sec. 3 Chung-Hsiao E. Rd., Taipei, Taiwan 10608. f10894@ntut.edu.tw
Chen
Chin-Wen
CW
Lin
Jin-Chung
JC
D000595:Amino Acid Sequence; D003198:Computer Simulation; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D005057:Eukaryotic Cells / Q000737:chemistry* / Q000502:physiology; D006801:Humans; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D024642:Potassium Channels, Voltage-Gated / Q000737:chemistry* / Q000502:physiology; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
D024642:Potassium Channels, Voltage-Gated