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.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Boland LM,Jurman ME,Yellen Gdoi
10.1016/s0006-3495(94)80843-4subject
Has Abstractpub_date
1994-03-01 00:00:00pages
694-9issue
3 Pt 1eissn
0006-3495issn
1542-0086pii
S0006-3495(94)80843-4journal_volume
66pub_type
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