3L1T

E. coli NrfA sulfite ocmplex

3L1T の概要

• エントリーDOI: 10.2210/pdb3l1t/pdb
• 関連するPDBエントリー: 2RDZ 3BNF
• 分子名称: Cytochrome c-552, CALCIUM ION, HEME C, ... (6 entities in total)
• 機能のキーワード: multiheme, sulfite, nitrite reductase, c-type cytochrome, electron transport, heme, iron, metal-binding, oxidoreductase, transport
• 由来する生物種: Escherichia coli
• 細胞内の位置: Periplasm: P0ABK9
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 216508.28

構造登録者

Clarke, T.A.,Hemmings, A.M.,Butt, J.N. (登録日: 2009-12-14, 公開日: 2010-10-27, 最終更新日: 2023-11-01)

主引用文献

Kemp, G.L.,Clarke, T.A.,Marritt, S.J.,Lockwood, C.,Poock, S.R.,Hemmings, A.M.,Richardson, D.J.,Cheesman, M.R.,Butt, J.N.
Kinetic and thermodynamic resolution of the interactions between sulfite and the pentahaem cytochrome NrfA from Escherichia coli
Biochem.J., 431:73-80, 2010

PubMed Abstract: NrfA is a pentahaem cytochrome present in a wide-range of γ-, δ- and ε-proteobacteria. Its nitrite and nitric oxide reductase activities have been studied extensively and contribute to respiratory nitrite ammonification and nitric oxide detoxification respectively. Sulfite is a third substrate for NrfA that may be encountered in the micro-oxic environments where nrfA is expressed. Consequently, we have performed quantitative kinetic and thermodynamic studies of the interactions between sulfite and Escherichia coli NrfA to provide a biochemical framework from which to consider their possible cellular consequences. A combination of voltammetric, spectroscopic and crystallographic analyses define dissociation constants for sulfite binding to NrfA in oxidized (~54 μM), semi-reduced (~145 μM) and reduced (~180 μM) states that are comparable with each other, and the Km (~70 μM) for sulfite reduction at pH 7. Under comparable conditions Km values of ~22 and ~300 μM describe nitrite and nitric oxide reduction respectively, whereas the affinities of nitrate and thiocyanate for NrfA fall more than 50-fold on enzyme reduction. These results are discussed in terms of the nature of sulfite co-ordination within the active site of NrfA and their implications for the cellular activity of NrfA.

PubMed: 20629638
DOI: 10.1042/BJ20100866

実験手法

X-RAY DIFFRACTION (2.3 Å)