MJK2, a K+Channel from M. Jannaschii Mediates pH Dependent Potassium Transport Activity

Download statistics - Document (COUNTER):

Zeilinger, Carsten: MJK2, a K+Channel from M. Jannaschii Mediates pH Dependent Potassium Transport Activity. In: Journal of Physical Chemistry & Biophysics 4 (2014), Nr. 5. DOI: dx.doi.org/10.4172/2161-0398.1000156

Repository version

To cite the version in the repository, please use this identifier: https://doi.org/10.15488/59

Selected time period:


Sum total of downloads: 129

MjK2 was expressed in E. coli cells as a fusion protein containing N-or C-terminal an antibody binding site and a histidinehexamer. The C-terminal tagged fusion protein allows the expression and purification of an extra soluble RCK domain at p34 kDa, whereas this additional RCK domain was lost when the N-terminal tagged construct was used. Upon removal of the fusion peptide from the purified N-terminal tagged channel monomer, MjK2 occurred as a stable tetramer when incubated with synthetic lipid. The channel activity was studied after reconstitution into liposomes by single channel recording or by an optical assay with the potassium sensing dye, PBFI. First the channel function was improved by single channel recording. Single channel recording confirmed the pH dependence of the channel activity with single channel conductances of 42, 70, 85 and 202 pS and indicated that a functional K+ channel was formed. To study the function of the reconstituted MjK2 activity in an optical assay the potassium release was initiated when the external BaCl2 block was compensated by addition of EDTA. The release of potassium was mediated by reconstituted MjK2 at low pH or by the presence of internal calcium at high pH. MgCl2 had no or weak effect, whereas cAMP at low pH caused a complete loss of potassium during the preparation. Alignments studies revealed that MjK2 has different structural features in the channel pore and the RCK composition and therefore a different function can be expected. Amino acid sequence and structural alignments showed that a Ca2+ binding site and a typical nucleotide-binding site is not present in the RCK domain of MjK2 and therefore a different behavior could be expected. In addition a lysine reach linker region as found in human sperm K+ channels hslo1 and hslo3can play similar role in the gating behavior.
License of this version: CC BY 4.0
Document Type: article
Publishing status: publishedVersion
Issue Date: 2014
Appears in Collections:Naturwissenschaftliche Fakultät

distribution of downloads over the selected time period:

downloads by country:

pos. country downloads
total perc.
1 image of flag of Germany Germany 94 72.87%
2 image of flag of China China 13 10.08%
3 image of flag of United States United States 8 6.20%
4 image of flag of Russian Federation Russian Federation 2 1.55%
5 image of flag of Japan Japan 2 1.55%
6 image of flag of Australia Australia 2 1.55%
7 image of flag of No geo information available No geo information available 1 0.78%
8 image of flag of Italy Italy 1 0.78%
9 image of flag of India India 1 0.78%
10 image of flag of France France 1 0.78%
    other countries 4 3.10%

Further download figures and rankings:


Zur Erhebung der Downloadstatistiken kommen entsprechend dem „COUNTER Code of Practice for e-Resources“ international anerkannte Regeln und Normen zur Anwendung. COUNTER ist eine internationale Non-Profit-Organisation, in der Bibliotheksverbände, Datenbankanbieter und Verlage gemeinsam an Standards zur Erhebung, Speicherung und Verarbeitung von Nutzungsdaten elektronischer Ressourcen arbeiten, welche so Objektivität und Vergleichbarkeit gewährleisten sollen. Es werden hierbei ausschließlich Zugriffe auf die entsprechenden Volltexte ausgewertet, keine Aufrufe der Website an sich.

Search the repository