1K4C

Potassium Channel KcsA-Fab complex in high concentration of K+

1K4C の概要

• エントリーDOI: 10.2210/pdb1k4c/pdb
• 分子名称: antibody Fab fragment heavy chain, antibody Fab fragment light chain, potassium channel KcsA, ... (7 entities in total)
• 機能のキーワード: k channel, protein-antibody fab complex, membrane protein
• 由来する生物種: Streptomyces lividans; 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: 61101.52

構造登録者

Zhou, Y.,Morais-Cabral, J.H.,Kaufman, A.,MacKinnon, R. (登録日: 2001-10-07, 公開日: 2001-11-14, 最終更新日: 2024-10-30)

主引用文献

Zhou, Y.,Morais-Cabral, J.H.,Kaufman, A.,MacKinnon, R.
Chemistry of ion coordination and hydration revealed by a K+ channel-Fab complex at 2.0 A resolution.
Nature, 414:43-48, 2001

PubMed Abstract: Ion transport proteins must remove an ion's hydration shell to coordinate the ion selectively on the basis of its size and charge. To discover how the K+ channel solves this fundamental aspect of ion conduction, we solved the structure of the KcsA K+ channel in complex with a monoclonal Fab antibody fragment at 2.0 A resolution. Here we show how the K+ channel displaces water molecules around an ion at its extracellular entryway, and how it holds a K+ ion in a square antiprism of water molecules in a cavity near its intracellular entryway. Carbonyl oxygen atoms within the selectivity filter form a very similar square antiprism around each K+ binding site, as if to mimic the waters of hydration. The selectivity filter changes its ion coordination structure in low K+ solutions. This structural change is crucial to the operation of the selectivity filter in the cellular context, where the K+ ion concentration near the selectivity filter varies in response to channel gating.

PubMed: 11689936
DOI: 10.1038/35102009

実験手法

X-RAY DIFFRACTION (2 Å)