6C3X

Wild type structure of SiRHP

6C3X の概要

• エントリーDOI: 10.2210/pdb6c3x/pdb
• 関連するPDBエントリー: 6C3M
• 分子名称: Sulfite reductase [NADPH] hemoprotein beta-component, PHOSPHATE ION, POTASSIUM ION, ... (6 entities in total)
• 機能のキーワード: redox, iron-sulfur cluster, fe4-s4 cluster, siroheme, iron, metal binding protein
• 由来する生物種: Escherichia coli (strain K12)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 65417.37

構造登録者

Stroupe, M.E. (登録日: 2018-01-11, 公開日: 2018-06-13, 最終更新日: 2023-12-27)

主引用文献

Cepeda, M.R.,McGarry, L.,Pennington, J.M.,Krzystek, J.,Stroupe, M.E.
The role of extended Fe4S4cluster ligands in mediating sulfite reductase hemoprotein activity.
Biochim. Biophys. Acta, 1866:933-940, 2018

PubMed Abstract: The siroheme-containing subunit from the multimeric hemoflavoprotein NADPH-dependent sulfite reductase (SiR/SiRHP) catalyzes the six electron-reduction of SO to S. Siroheme is an iron-containing isobacteriochlorin that is found in sulfite and homologous siroheme-containing nitrite reductases. Siroheme does not work alone but is covalently coupled to a FeS cluster through one of the cluster's ligands. One long-standing hypothesis predicted from this observation is that the environment of one iron-containing cofactor influences the properties of the other. We tested this hypothesis by identifying three amino acids (F437, M444, and T477) that interact with the FeS cluster and probing the effect of altering them to alanine on the function and structure of the resulting enzymes by use of activity assays, X-ray crystallographic analysis, and EPR spectroscopy. We showed that F437 and M444 gate access for electron transfer to the siroheme-cluster assembly and the direct hydrogen bond between T477 and one of the cluster sulfides is important for determining the geometry of the siroheme active site.

PubMed: 29852252
DOI: 10.1016/j.bbapap.2018.05.013

実験手法

X-RAY DIFFRACTION (1.542 Å)