2NOW

An unusual twin-His arrangement in the pore of ammonia channels is essential for substrate conductance

2NOW の概要

• エントリーDOI: 10.2210/pdb2now/pdb
• 関連するPDBエントリー: 1U7G 1XQE 1XQF 2NMR 2NOP 2NPC 2NPD 2NPE 2NPG 2NPJ 2NPK
• 分子名称: Ammonia channel, SULFATE ION, ACETATE ION, ... (5 entities in total)
• 機能のキーワード: membrane protein, ammonia transport, histidine mutant, amtb, transport protein
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cell inner membrane; Multi-pass membrane protein: P69681
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 44785.94

構造登録者

Lupo, D.,Winkler, F.K. (登録日: 2006-10-26, 公開日: 2006-11-14, 最終更新日: 2023-10-25)

主引用文献

Javelle, A.,Lupo, D.,Zheng, L.,Li, X.-D.,Winkler, F.K.,Merrick, M.
An unusual twin-his arrangement in the pore of ammonia channels is essential for substrate conductance
J.Biol.Chem., 281:39492-39498, 2006

PubMed Abstract: Amt proteins constitute a class of ubiquitous integral membrane proteins that mediate movement of ammonium across cell membranes. They are homotrimers, in which each subunit contains a narrow pore through which substrate transport occurs. Two conserved histidine residues in the pore have been proposed to be necessary for ammonia conductance. By analyzing 14 engineered polar and non-polar variants of these histidines, in Escherichia coli AmtB, we show that both histidines are absolutely required for optimum substrate conductance. Crystal structures of variants confirm that substitution of the histidine residues does not affect AmtB structure. In a subgroup of Amt proteins, found only in fungi, one of the histidines is replaced by glutamate. The equivalent substitution in E. coli AmtB is partially active, and the structure of this variant suggests that the glutamate side chain can make similar interactions to those made by histidine.

PubMed: 17040913
DOI: 10.1074/jbc.M608325200

実験手法

X-RAY DIFFRACTION (2.2 Å)