4FC4

FNT family ion channel

4FC4 の概要

• エントリーDOI: 10.2210/pdb4fc4/pdb
• 関連するPDBエントリー: 3Q7K
• 分子名称: Nitrite transporter NirC, octyl beta-D-glucopyranoside (3 entities in total)
• 機能のキーワード: alpha-helical inner membrane protein, ion channel, cytoplasmic membrane, transport protein
• 由来する生物種: Salmonella enterica subsp. enterica serovar Typhimurium
• タンパク質・核酸の鎖数: 10
• 化学式量合計: 281382.53

構造登録者

Lue, W.,Schwarzer, N.,Du, J.,Gerbig-Smentek, E.,Andrade, S.L.A.,Einsle, O. (登録日: 2012-05-24, 公開日: 2012-11-21, 最終更新日: 2023-09-13)

主引用文献

Lu, W.,Schwarzer, N.J.,Du, J.,Gerbig-Smentek, E.,Andrade, S.L.,Einsle, O.
Structural and functional characterization of the nitrite channel NirC from Salmonella typhimurium.
Proc.Natl.Acad.Sci.USA, 109:18395-18400, 2012

PubMed Abstract: Nitrite (NO(2)(-)) is a central intermediate in the nitrogen metabolism of microorganisms and plants, and is used as a cytotoxin by macrophages as part of the innate immune response. The bacterial membrane protein NirC acts as a specific channel to facilitate the transport of nitrite anions across lipid bilayers for cytoplasmic detoxification. Despite NirC's importance in nitrogen metabolism and in the pathogenicity of enteric bacteria, available biochemical data are scarce. Here we present a functional and structural characterization of NirC from Salmonella typhimurium by lipid bilayer electrophysiology and X-ray crystallography. NirC is a pentameric member of the formate/nitrite transporter family of membrane proteins that operates as a channel with high conductance. Single-channel measurements reveal fast and slow gating events but, in contrast to the related FocA formate channel, no pH-dependent gating. A 2.4Å crystal structure of NirC at pH 5 shows similarity to FocA and aquaporins, but lacks the structural asymmetry observed in the formate channel at similarly low pH. Resolved water molecules in the protomers suggest a transport mechanism that also permits a facultative NO(2)(-)/H(+) symport.

PubMed: 23090993
DOI: 10.1073/pnas.1210793109

実験手法

X-RAY DIFFRACTION (2.4 Å)