Molecular properties of Kcv, a virus encoded K+ channel

Cinzia Pagliuca, Tom Alexander Goetze, Richard Wagner, Gerhard Thiel, Anna Moroni, David Parcej

Research output: Contribution to journalArticlepeer-review

Abstract

The miniature viral K+ channel Kcv represents the pore module of all K+ channels. A synthetic gene of Kcv with an elevated GC content compared to that of the wild-type gene was expressed heterologously in Pichia pastoris, and the purified protein was functionally reconstituted into liposomes. Biochemical assays reveal a remarkable cation selective stability of the channel tetramer via SDS-PAGE. Only cations, which permeate Kcv, were able to protect the oligomer against disassembly into monomers at high temperatures. Electrophysiological characterization of the single Kcv channel reveals a saturating conductance (Δmax) of 360 pS; the single-channel current-voltage relation was strongly rectifying with a negative slope conductance at extreme voltages. The channel was highly selective for K + and was blocked by Ba2+ and in a side specific manner by Na+ and Cs+ also. The channel conducted Rb+, but as a consequence, the channel was shifted into a hyperactive state. We conclude that specific binding interactions of cations in the conductive pathway are an important determinant of channel stability and function.

Original languageEnglish
Pages (from-to)1079-1090
Number of pages12
JournalBiochemistry
Volume46
Issue number4
DOIs
Publication statusPublished - Jan 30 2007

ASJC Scopus subject areas

  • Biochemistry

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