Probing of pore in the Chara gymnophylla K+ channel by blocking cations and by streaming potential measurements

FEBS Letters

Pottosin, Igor I.¹ 

[1] Laboratory of Membrane Biophysics, Institute of Cell Biophysics, USSR Academy of Sciences, Pushchino, 142292, USSR

关键词: K+ channel;    Ca2+-dependent;    Chara;    Patch-clamp;    Ion block;    Streaming potential;    TEA+;    tetraethylammonium;    TMA+;    tetramethylammonium;    TBA+;    tetrabuthylammonium HEPES;    4-(2-Hydroxyethyl)piperazine-I-ethanesulfonic acid;    EDTA;    ethylenediaminetetraacetic acid;   

DOI  :  10.1016/0014-5793(92)80070-W

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The current—voltage (I–V) relationship of single K⁺ channels present in the Chara gymnophylla droplet membrane was studied. The channel presumably contains large mouths at both pore ends which are sufficiently wide to accomodate TEA⁺ as evidenced by internal and external TEA⁺ blockade. The voltage dependence of blockade by external Cs⁺ and Na⁺ reveals the multi-ion occupancy of the channel. The value of streaming potential (4.0 mV/osmol) measured in the Chara K⁺ channel indicates that the channel contains up to nine water molecules in the narrow region. It is concluded that the length of this region is around 28 Å.

【 授权许可】

Unknown