3OGC

KcsA E71A variant in presence of Na+

3OGC の概要

• エントリーDOI: 10.2210/pdb3ogc/pdb
• 分子名称: antibody Fab fragment heavy chain, antibody Fab fragment light chain, Voltage-gated potassium channel, ... (4 entities in total)
• 機能のキーワード: voltage-gated channel, antibody fab complex, membrane protein
• 由来する生物種: Mus musculus (mouse); 詳細
• 細胞内の位置: Cell membrane; Multi-pass membrane protein: P0A334
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 60998.52

構造登録者

McCoy, J.G.,Nimigean, C.M. (登録日: 2010-08-16, 公開日: 2011-03-16, 最終更新日: 2024-11-27)

主引用文献

Cheng, W.W.,McCoy, J.G.,Thompson, A.N.,Nichols, C.G.,Nimigean, C.M.
Mechanism for selectivity-inactivation coupling in KcsA potassium channels.
Proc.Natl.Acad.Sci.USA, 108:5272-5277, 2011

PubMed Abstract: Structures of the prokaryotic K(+) channel, KcsA, highlight the role of the selectivity filter carbonyls from the GYG signature sequence in determining a highly selective pore, but channels displaying this sequence vary widely in their cation selectivity. Furthermore, variable selectivity can be found within the same channel during a process called C-type inactivation. We investigated the mechanism for changes in selectivity associated with inactivation in a model K(+) channel, KcsA. We found that E71A, a noninactivating KcsA mutant in which a hydrogen-bond behind the selectivity filter is disrupted, also displays decreased K(+) selectivity. In E71A channels, Na(+) permeates at higher rates as seen with and flux measurements and analysis of intracellular Na(+) block. Crystal structures of E71A reveal that the selectivity filter no longer assumes the "collapsed," presumed inactivated, conformation in low K(+), but a "flipped" conformation, that is also observed in high K(+), high Na(+), and even Na(+) only conditions. The data reveal the importance of the E71-D80 interaction in both favoring inactivation and maintaining high K(+) selectivity. We propose a molecular mechanism by which inactivation and K(+) selectivity are linked, a mechanism that may also be at work in other channels containing the canonical GYG signature sequence.

PubMed: 21402935
DOI: 10.1073/pnas.1014186108

実験手法

X-RAY DIFFRACTION (3.8 Å)