KcsA Barium Permeation Blocked by External Potassium
نویسندگان
چکیده
منابع مشابه
Potassium-selective block of barium permeation through single KcsA channels
Ba(2+), a doubly charged analogue of K(+), specifically blocks K(+) channels by virtue of electrostatic stabilization in the permeation pathway. Ba(2+) block is used here as a tool to determine the equilibrium binding affinity for various monovalent cations at specific sites in the selectivity filter of a noninactivating mutant of KcsA. At high concentrations of external K(+), the block-time di...
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Single high-conductance Ca2+-activated K+ channels from rat skeletal muscle were inserted into planar lipid bilayers, and discrete blocking by the Ba2+ ion was studied. Specifically, the ability of external K+ to reduce the Ba2+ dissociation rate was investigated. In the presence of 150 mM internal K+, 1-5 microM internal Ba2+, and 150 mM external Na+, Ba2+ dissociation is rapid (5 s-1) in exte...
متن کاملPotassium permeation through the KcsA channel: a density functional study.
We present a theoretical study on structural and electronic aspects of K+ permeation through the binding sites of the KcsA channel's selectivity filter. Density functional calculations are carried out on models taken from selected snapshots of a molecular dynamics simulation recently reported [FEBS Lett. 477 (2000) 37]. During the translocation process from one binding site to the other, the co...
متن کاملModeling the concentration-dependent permeation modes of the KcsA potassium ion channel.
The potassium channel from Streptomyces lividans (KcsA) is an integral membrane protein with sequence similarity to all known potassium channels, particularly in the selectivity filter region. A recently proposed model for ion channels containing either n or (n-1) single-file ions in their selectivity filters [P. H. Nelson, J. Chem. Phys. 177, 11396 (2002)] is applied to published KcsA channel ...
متن کاملSimulations of ion permeation through a potassium channel: molecular dynamics of KcsA in a phospholipid bilayer.
Potassium channels enable K(+) ions to move passively across biological membranes. Multiple nanosecond-duration molecular dynamics simulations (total simulation time 5 ns) of a bacterial potassium channel (KcsA) embedded in a phospholipid bilayer reveal motions of ions, water, and protein. Comparison of simulations with and without K(+) ions indicate that the absence of ions destabilizes the st...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2010
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2009.12.627