5ER7

Connexin-26 Bound to Calcium

5ER7 の概要

• エントリーDOI: 10.2210/pdb5er7/pdb
• 関連するPDBエントリー: 5ERA
• 分子名称: Gap junction beta-2 protein, CALCIUM ION (2 entities in total)
• 機能のキーワード: gap junction, ion channel, calcium binding, electrostatic gating, calcium binding protein
• 由来する生物種: Homo sapiens (Human)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 52357.85

構造登録者

Purdy, M.D.,Bennett, B.C.,Baker, K.A.,Yeager, M.J. (登録日: 2015-11-13, 公開日: 2016-01-27, 最終更新日: 2024-11-06)

主引用文献

Bennett, B.C.,Purdy, M.D.,Baker, K.A.,Acharya, C.,McIntire, W.E.,Stevens, R.C.,Zhang, Q.,Harris, A.L.,Abagyan, R.,Yeager, M.
An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels.
Nat Commun, 7:8770-8770, 2016

PubMed Abstract: Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). The two structures were nearly identical, ruling out both a large-scale structural change and a local steric constriction of the pore. Ca(2+) coordination sites reside at the interfaces between adjacent subunits, near the entrance to the extracellular gap, where local, side chain conformational rearrangements enable Ca(2+)chelation. Computational analysis revealed that Ca(2+)-binding generates a positive electrostatic barrier that substantially inhibits permeation of cations such as K(+) into the pore. Our results provide structural evidence for a unique mechanism of channel regulation: ionic conduction block via an electrostatic barrier rather than steric occlusion of the channel pore.

PubMed: 26753910
DOI: 10.1038/ncomms9770

実験手法

X-RAY DIFFRACTION (3.286 Å)