2RF1

Crystal structure of ChoX in an unliganded closed conformation

2RF1 の概要

• エントリーDOI: 10.2210/pdb2rf1/pdb
• 関連するPDBエントリー: 2REG 2REJ 2RIN
• 分子名称: PUTATIVE GLYCINE BETAINE-BINDING ABC TRANSPORTER PROTEIN (2 entities in total)
• 機能のキーワード: type ii binding protein, aromatic box, abc-transporter, transport protein
• 由来する生物種: Rhizobium meliloti (Sinorhizobium meliloti)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 64604.03

構造登録者

Oswald, C.,Smits, S.H.J.,Hoeing, M.,Sohn-Boeser, L.,Le Rudulier, D.,Schmitt, L.,Bremer, E. (登録日: 2007-09-27, 公開日: 2008-09-16, 最終更新日: 2024-10-30)

主引用文献

Oswald, C.,Smits, S.H.,Hoing, M.,Sohn-Bosser, L.,Dupont, L.,Le Rudulier, D.,Schmitt, L.,Bremer, E.
Crystal structures of the choline/acetylcholine substrate-binding protein ChoX from Sinorhizobium meliloti in the liganded and unliganded-closed states.
J.Biol.Chem., 283:32848-32859, 2008

PubMed Abstract: The ATP-binding cassette transporter ChoVWX is one of several choline import systems operating in Sinorhizobium meliloti. Here fluorescence-based ligand binding assays were used to quantitate substrate binding by the periplasmic ligand-binding protein ChoX. These data confirmed that ChoX recognizes choline and acetylcholine with high and medium affinity, respectively. We also report the crystal structures of ChoX in complex with either choline or acetylcholine. These structural investigations revealed an architecture of the ChoX binding pocket and mode of substrate binding similar to that reported previously for several compatible solute-binding proteins. Additionally the ChoX-acetylcholine complex permitted a detailed structural comparison with the carbamylcholine-binding site of the acetylcholine-binding protein from the mollusc Lymnaea stagnalis. In addition to the two liganded structures of ChoX, we were also able to solve the crystal structure of ChoX in a closed, substrate-free conformation that revealed an architecture of the ligand-binding site that is superimposable to the closed, ligand-bound form of ChoX. This structure is only the second of its kind and raises the important question of how ATP-binding cassette transporters are capable of distinguishing liganded and unliganded-closed states of the binding protein.

PubMed: 18779321
DOI: 10.1074/jbc.M806021200

実験手法

X-RAY DIFFRACTION (2 Å)