3BNH

W. succinogenes NrfA Y218F Nitrite Complex

3BNH の概要

• エントリーDOI: 10.2210/pdb3bnh/pdb
• 関連するPDBエントリー: 1FS7 3BNF 3BNG 3BNJ
• 分子名称: Cytochrome c-552, NITRITE ION, CALCIUM ION, ... (8 entities in total)
• 機能のキーワード: c-type cytochrome, nitrite reductase, nitrite complex, calcium, electron transport, heme, iron, metal-binding, oxidoreductase, periplasm, transport
• 由来する生物種: Wolinella succinogenes
• 細胞内の位置: Periplasm: Q9S1E5
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 58976.99

構造登録者

Lukat, P.,Einsle, O. (登録日: 2007-12-14, 公開日: 2008-02-26, 最終更新日: 2023-11-01)

主引用文献

Lukat, P.,Rudolf, M.,Stach, P.,Messerschmidt, A.,Kroneck, P.M.H.,Simon, J.,Einsle, O.
Binding and Reduction of Sulfite by Cytochrome c Nitrite Reductase
Biochemistry, 47:2080-2086, 2008

PubMed Abstract: Pentaheme cytochrome c nitrite reductase (ccNiR) catalyzes the six-electron reduction of nitrite to ammonia as the final step in the dissimilatory pathway of nitrate ammonification. It has also been shown to reduce sulfite to sulfide, thus forming the only known link between the biogeochemical cycles of nitrogen and of sulfur. We have found the sulfite reductase activity of ccNiR from Wolinella succinogenes to be significantly smaller than its nitrite reductase activity but still several times higher than the one described for dissimilatory, siroheme-containing sulfite reductases. To compare the sulfite reductase activity of ccNiR with our previous data on nitrite reduction, we determined the binding mode of sulfite to the catalytic heme center of ccNiR from W. succinogenes at a resolution of 1.7 A. Sulfite and nitrite both provide a pair of electrons to form the coordinative bond to the Fe(III) active site of the enzyme, and the oxygen atoms of sulfite are found to interact with the three active site protein residues conserved within the enzyme family. Furthermore, we have characterized the active site variant Y218F of ccNiR that exhibited an almost complete loss of nitrite reductase activity, while sulfite reduction remained unaffected. These data provide a first direct insight into the role of the first sphere of protein ligands at the active site in ccNiR catalysis.

PubMed: 18201106
DOI: 10.1021/bi7021415

実験手法

X-RAY DIFFRACTION (1.75 Å)