Journal
JOURNAL OF GENERAL PHYSIOLOGY
Volume 118, Issue 3, Pages 303-313Publisher
ROCKEFELLER UNIV PRESS
DOI: 10.1085/jgp.118.3.303
Keywords
ion conductivity; selectivity
Categories
Funding
- NIGMS NIH HHS [R37 GM031768, R01 GM031768, GM31768] Funding Source: Medline
Ask authors/readers for more resources
Ion conduction and selectivity properties of KcsA. a bacterial ion channel of known structure, were studied in a planar lipid bilayer system at the single-channel level. Selectivity sequences for permeant ions were determined b, mrimietrical Solution conductance (K+ > Rb-, NH4+, Tl+ > Cs+, Na+, Li+) and by reversal potentials tinder bi-ionic or mixed-ion conditions (Tl+ > K+ > Rb+ > NH4+ > Na+, Li+). Determination of reversal potentials with submillivolt accuracy shows that K+ is over 150-fold more permeant than Na+. Variation of conductance with concentration under symmetrical salt conditions is complex, with at least two ion-binding processes revealing themselves: a high affinity process below 20 mM and a low affinity process over the range 100-1,000 mM. These properties are analogous to those seen in many eukaryotic K+ channels, and they establish KcsA as a faithful structural model for ion permeation in eukaryotic K+ channels.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available