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Functional Studies of Synthetic Gramicidin Hybrid Ion Channels in CHO Cells
Author(s) -
Wesolowski Ryszard,
Sommer Anna,
Arndt HansDieter,
Koert Ulrich,
Reiß Philipp,
Wimmers Sönke,
Strauss Olaf
Publication year - 2007
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200600384
Subject(s) - chinese hamster ovary cell , ion channel , gramicidin , chemistry , biophysics , extracellular , patch clamp , lipid bilayer , membrane , conductance , membrane potential , biochemistry , biology , receptor , mathematics , combinatorics
The function of a gramicidin hybrid ion channel in living Chinese hamster ovary (CHO) cells was investigated by the patch clamp method. The synthetic ion channel 1 consists of two cyclohexyl ether amino acids that link two minigramicidin strands. With 1 at a concentration of 1.0 μ M , an increase in the whole‐cell membrane conductance was observed after 1.37 min. The conductance showed larger currents when Cs + was used as charge carrier than when Na + and K + were used. In single‐channel recordings with Cs + as charge carrier, the substance showed comparable single‐channel amplitudes in the membrane of living cells and artificial black lipid bilayers. In addition to functioning as a cation channel, compound 1 appeared to be a water channel. Exposure of the CHO cells to an extracellular hypoosmotic solution did not substantially change the cell volume. Extracellular hypoosmotic conditions in the presence of 1 increased the cell size to 146.5 % that of the control. Thus, the synthetic hybrid channel 1 can function as a cation channel with some Cs + specificity, and as a water channel in CHO cells.