English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We show that interactions of fatty acids with the central cavity of potassium channel KcsA can be characterized using the fluorescence probe 11-dansylaminoundecanoic acid (Dauda). The fluorescence emission spectrum of Dauda bound to KcsA in bilayers of dioleoylphosphatidylcholine contains three components, which can be attributed to KcsA-bound and lipid-bound Dauda together with unbound Dauda. The binding of Dauda to KcsA was characterized by a dissociation constant of 0.47 ± 0.10 μM with 0.94 ± 0.06 binding site per KcsA tetramer. Displacement of KcsA-bound Dauda by the tetrabutylammonium (TBA) ion confirmed that the Dauda binding site was in the central cavity of KcsA. Dissociation constants for a range of fatty acids were determined by displacement of Dauda: binding of fatty acids increased in strength with an increasing chain length from C14 to C20 but then decreased in strength from C20 to C22. Increasing the number of double bonds in the chain from one to four had little effect on binding, dissociation constants for oleic acid and arachidonic acid, for example, being 2.9 ± 0.2 and 3.0 ± 0.4 μM, respectively. Binding of TBA to KcsA was very slow, whereas binding of Dauda was fast, suggesting that TBA can enter the cavity only through an open channel whereas Dauda can bind to the closed channel, presumably entering the cavity via the lipid bilayer.

Characterizing the Fatty Acid Binding Site in the Cavity of Potassium Channel KcsA