Skip to main content

Free Content GCN4 enhances the stability of the pore domain of potassium channel KcsA

Download Article:

You have access to the full text article on a website external to Ingenta Connect.

Please click here to view this article on Wiley Online Library.

You may be required to register and activate access on Wiley Online Library before you can obtain the full text. If you have any queries please visit Wiley Online Library

The prokaryotic potassium channel from Streptomyces lividans, KcsA, is the first channel that has a known crystal structure of the transmembrane domain. The crystal structure of its soluble C-terminal domain, however, still remains elusive. Biophysical and electrophysiological studies have previously implicated the essential roles of the C-terminal domain in pH sensing and in vivo channel assembly. We examined this functional assignment by replacing the C-terminal domain with an artificial tetramerization domain, GCN4-LI. The expression of KcsA is completely abolished when its C-terminal domain is deleted, but it can be rescued by fusion with GCN4-LI. The secondary and quaternary structures of the hybrid channel are very similar to those of the wild-type channel according to CD and gel-filtration analyses. The thermostability of the hybrid channel at pH 8 is similar to that of the wild-type but is insensitive to pH changes. This supports the notion that the pH sensor of KcsA is located in the C-terminal domain. The result obtained in the present study is in agreement with the proposed functions of the C-terminal domain and we show that the channel assembly role of the C-terminal domain can be substituted with a non-native tetrameric motif. Because tetramerization domains are found in different families of potassium channels and their presence often enhances the expression of channels, replacement of the elusive C-terminal domains with a known tetrameric scaffold could potentially assist the expression of other potassium channels.
No References
No Citations
No Supplementary Data
No Data/Media
No Metrics

Keywords: GCN4; KcsA; pore domain; potassium channel; tetramerization domain

Document Type: Research Article

Publication date: 2008-12-01

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more