2CCD

Crystal structure of the catalase-peroxidase (KatG) and S315T mutant from Mycobacterium tuberculosis

2CCD の概要

• エントリーDOI: 10.2210/pdb2ccd/pdb
• 関連するPDBエントリー: 1SFZ 1SJ2 2CC4 2CCA
• 分子名称: PEROXIDASE/CATALASE T, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: oxidoreductase, katg, hydrogen peroxide, iron, metal-binding
• 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: 162636.24

構造登録者

Yu, H.,Sacchettini, J.C. (登録日: 2006-01-16, 公開日: 2006-01-19, 最終更新日: 2023-12-13)

主引用文献

Zhao, X.,Yu, H.,Yu, S.,Wang, F.,Sacchettini, J.C.,Magliozzo, R.S.
Hydrogen Peroxide-Mediated Isoniazid Activation Catalyzed by Mycobacterium Tuberculosis Catalase- Peroxidase (Katg) and its S315T Mutant.
Biochemistry, 45:4131-, 2006

PubMed Abstract: Inhibition of the enzyme Mycobacterium tuberculosis InhA (enoyl-acyl carrier protein reductase) due to formation of an isonicotinoyl-NAD adduct (IN-NAD) from isoniazid (INH) and nicotinamide adenine dinucleotide cofactor is considered central to the mode of action of INH, a first-line treatment for tuberculosis infection. INH action against mycobacteria requires catalase-peroxidase (KatG) function, and IN-NAD adduct formation is catalyzed in vitro by M. tuberculosis KatG under a variety of conditions, yet a physiologically relevant approach to the process has not emerged that allows scrutiny of the mechanism and the origins of INH resistance in the most prevalent drug-resistant strain bearing KatG[S315T]. In this report, we describe how hydrogen peroxide, delivered at very low concentrations to ferric KatG, leads to efficient inhibition of InhA due to formation of the IN-NAD adduct. The rate of adduct formation mediated by wild-type KatG was about 20-fold greater than by the isoniazid-resistant KatG[S315T] mutant under optimal conditions (H2O2 supplied along with NAD+ and INH). Slow adduct formation also occurs starting with NADH and INH, in the presence of KatG even in the absence of added peroxide, due to endogenous peroxide. The poor efficiency of the KatG[S315T] mutant can be enhanced merely by increasing the concentration of INH, consistent with this enzyme's reduced affinity for INH binding to the resting enzyme and the catalytically competent enzyme intermediate (Compound I). Origins of drug resistance in the KatG[S315T] mutant enzyme are analyzed at the structural level through examination of the three-dimensional X-ray crystal structure of the mutant enzyme.

PubMed: 16566587
DOI: 10.1021/BI051967O

実験手法

X-RAY DIFFRACTION (2.1 Å)