Conformational changes in the C terminus of Shaker K+ channel bound to the rat Kvbeta2-subunit.
We studied the structure of the C terminus of the Shaker potassium channel. The 3D structures of the full-length and a C-terminal deletion (Delta C) mutant of Shaker were determined by electron microscopy and single-particle analysis. The difference map between the full-length and the truncated channels clearly shows a compact density, located on the sides of the T1 domain, that corresponds to a large part of the C terminus. We also expressed and purified both WT and Delta C Shaker, assembled with the rat KvBeta2-subunit. By using a difference map between the full-length and truncated Shaker alpha-beta complexes, a conformational change was identified that shifts a large part of the C terminus away from the membrane domain and into close contact with the Beta-subunit. This conformational change, induced by the binding of the KvBeta2-subunit, suggests a possible mechanism for the modulation of the K+ voltage-gated channel function by its Beta-subunit.
Howard Hughes Medical Institute and Department of Biochemistry, Brandeis University, 415 South Street, Waltham, MA 02454-9110, USA.
Olga
O
Sokolova
Alessio
A
Accardi
David
D
Gutierrez
Adrian
A
Lau
Mike
M
Rigney
Nikolaus
N
Grigorieff
D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002522:Chlorocebus aethiops; D005583:Fourier Analysis; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics; D024642:Potassium Channels, Voltage-Gated; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D015183:Restriction Mapping; D051637:Shaker Superfamily of Potassium Channels; D014162:Transfection
C426239:Kcnab2 protein, rat; D010446:Peptide Fragments; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D021122:Protein Subunits; D011994:Recombinant Proteins; D051637:Shaker Superfamily of Potassium Channels