1ZJ9

Structure of Mycobacterium tuberculosis NirA protein

1ZJ9 の概要

• エントリーDOI: 10.2210/pdb1zj9/pdb
• 関連するPDBエントリー: 1ZJ8
• 分子名称: Probable ferredoxin-dependent nitrite reductase NirA, CHLORIDE ION, IRON/SULFUR CLUSTER, ... (5 entities in total)
• 機能のキーワード: nira, sulfite, nitrite, reductase, siroheme, fe4-s4, cys-tyr covalent bond, oxidoreductase
• 由来する生物種: Mycobacterium tuberculosis
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 129579.20

構造登録者

Schnell, R.,Sandalova, T.,Hellman, U.,Lindqvist, Y.,Schneider, G. (登録日: 2005-04-28, 公開日: 2005-05-31, 最終更新日: 2024-10-23)

主引用文献

Schnell, R.,Sandalova, T.,Hellman, U.,Lindqvist, Y.,Schneider, G.
Siroheme- and [Fe4-S4]-dependent NirA from Mycobacterium tuberculosis Is a Sulfite Reductase with a Covalent Cys-Tyr Bond in the Active Site
J.Biol.Chem., 280:27319-27328, 2005

PubMed Abstract: The nirA gene of Mycobacterium tuberculosis is up-regulated in the persistent state of the bacteria, suggesting that it is a potential target for the development of antituberculosis agents particularly active against the pathogen in its dormant phase. This gene encodes a ferredoxin-dependent sulfite reductase, and the structure of the enzyme has been determined using x-ray crystallography. The enzyme is a monomer comprising 555 amino acids and contains a [Fe4-S4] cluster and a siroheme cofactor. The molecule is built up of three domains with an alpha/beta fold. The first domain consists of two ferredoxin-like subdomains, related by a pseudo-2-fold symmetry axis passing through the whole molecule. The other two domains, which provide much of the binding interactions with the cofactors, have a common fold that is unique to the sulfite/nitrite reductase family. The domains form a trilobal structure, with the cofactors and the active site located at the interface of all three domains in the center of the molecule. NirA contains an unusual covalent bond between the side chains of Tyr69 and Cys161 in the active site, in close proximity to the siroheme cofactor. Removal of this covalent bond by site-directed mutagenesis impairs catalytic activity, suggesting that it is important for the enzymatic reaction. These residues are part of a sequence fingerprint, able to distinguish between ferredoxin-dependent sulfite and nitrite reductases. Comparison of NirA with the structure of the truncated NADPH-dependent sulfite reductase from Escherichia coli suggests a binding site for the external electron donor ferredoxin close to the [Fe4-S4] cluster.

PubMed: 15917234
DOI: 10.1074/jbc.M502560200

実験手法

X-RAY DIFFRACTION (2.9 Å)