HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ludewig, U Articles by Pusch, M Search for Related Content PubMed PubMed Citation Articles by Ludewig, U Articles by Pusch, M

Centre for Molecular Neurobiology (ZMNH), Hamburg University, Germany.

1. The chloride channel from the Torpedo electric organ, ClC-0, is controlled by two distinct ('fast' and 'slow') voltage-dependent gates. Here we investigate the effects of mutations in a region after putative transmembrane domain D12. A mutation in this region has previously been shown to change fast gating and permeation. 2. We used a combination of site-directed mutagenesis with two-electrode voltage-clamp and patch-clamp measurements. 3. Most conservative substitutions have minor effects, while more drastic mutations change kinetics and voltage dependence of fast gating, as well as ion selectivity and rectification. 4. While ClC-0 wild-type (WT) channels deactivate fully in two-electrode voltage clamp at negative voltages, channels do not close completely in patch-clamp experiments. Open probability is increased by intracellular chloride in a concentration- but not voltage-dependent manner. 5. In several mutants, including K519R, the minimal macroscopic open probability of fast gating is larger than in WT. Mutant channels fluctuate at negative potentials between open and closed conformations. Open probability is much more effectively increased by intracellular chloride than in WT. The observations support the idea that permeating ions inside the pore stabilize the open state. 6. Besides effects on permeation and gating of single protopores, some mutations affect 'slow' gating. In summary, the region after D12 participates in fast as well as in slow gating; mutations additionally influence permeation properties.

This article has been cited by other articles:

				T.-Y. Chen and T.-C. Hwang CLC-0 and CFTR: Chloride Channels Evolved From Transporters Physiol Rev, April 1, 2008; 88(2): 351 - 387. [Abstract] [Full Text] [PDF]

				R. Estevez, M. Pusch, C. Ferrer-Costa, M. Orozco, and T. J. Jentsch Functional and structural conservation of CBS domains from CLC chloride channels J. Physiol., June 1, 2004; 557(2): 363 - 378. [Abstract] [Full Text] [PDF]