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Cysteines in the Shaker K+ channel are not essential for channel activity or zinc modulation.

Cysteines in the Shaker K+ channel are not essential for channel activity or zinc modulation.

Authors :
Boland LM
Jurman ME
Yellen G
Source :
Biophysical journal [Biophys J] 1994 Mar; Vol. 66 (3 Pt 1), pp. 694-9.
Publication Year :
1994

Abstract

We investigated whether the cysteine residues in Shaker potassium (K+) channels are essential for activation and inactivation gating or for modulation of activation gating by external zinc (Zn2+). Mutants of the Shaker K+ channel were prepared in which all seven cysteine residues were replaced (C-less). These changes were made in both wild-type Shaker H4 channels and in a deletion mutant (delta 6-46) lacking N-type ("fast") inactivation. Replacement of all cysteines left most functional properties of the K+ currents unaltered. The most noticeable difference between the C-less and wild-type currents was the faster C-type inactivation of the C-less channel which could be attributed largely to the mutation of Cys462. This is consistent with the effects of previously reported mutations of nearby residues in the S6 region. There were also small changes in the activation gating of C-less currents. Modulation by external Zn2+ of the voltage dependence and rate of activation gating is preserved in the C-less channels, indicating that none of the cysteines in the Shaker K+ channel plays an important role in Zn2+ modulation.

Details

Language :
English
ISSN :
0006-3495
Volume :
66
Issue :
3 Pt 1
Database :
MEDLINE
Journal :
Biophysical journal
Publication Type :
Academic Journal
Accession number :
8011900
Full Text :
https://doi.org/10.1016/s0006-3495(94)80843-4