4CDP

Improved coordinates for Escherichia coli O157:H7 heme degrading enzyme ChuS.

「2HQ2」から置き換えられました

4CDP の概要

• エントリーDOI: 10.2210/pdb4cdp/pdb
• 分子名称: PUTATIVE HEME/HEMOGLOBIN TRANSPORT PROTEIN, FORMIC ACID, PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total)
• 機能のキーワード: heme degradation, structural repeat, montreal- kingston bacterial structural genomics initiative, bsgi, oxidoreductase
• 由来する生物種: ESCHERICHIA COLI
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 41487.41

構造登録者

Suits, M.D.L.,Jaffer, N.,Jia, Z. (登録日: 2013-11-05, 公開日: 2013-11-13, 最終更新日: 2023-12-20)

主引用文献

Suits, M.D.,Jaffer, N.,Jia, Z.
Structure of the Escherichia Coli O157:H7 Heme Oxygenase Chus in Complex with Heme and Enzymatic Inactivation by Mutation of the Heme Coordinating Residue His-193.
J.Biol.Chem., 281:36776-, 2006

PubMed Abstract: Heme oxygenases catalyze the oxidation of heme to biliverdin, CO, and free iron. For pathogenic microorganisms, heme uptake and degradation are critical mechanisms for iron acquisition that enable multiplication and survival within hosts they invade. Here we report the first crystal structure of the pathogenic Escherichia coli O157:H7 heme oxygenase ChuS in complex with heme at 1.45 A resolution. When compared with other heme oxygenases, ChuS has a unique fold, including structural repeats and a beta-sheet core. Not surprisingly, the mode of heme coordination by ChuS is also distinct, whereby heme is largely stabilized by residues from the C-terminal domain, assisted by a distant arginine from the N-terminal domain. Upon heme binding, there is no large conformational change beyond the fine tuning of a key histidine (His-193) residue. Most intriguingly, in contrast to other heme oxygenases, the propionic side chains of heme are orientated toward the protein core, exposing the alpha-meso carbon position where O(2) is added during heme degradation. This unique orientation may facilitate presentation to an electron donor, explaining the significantly reduced concentration of ascorbic acid needed for the reaction. Based on the ChuS-heme structure, we converted the histidine residue responsible for axial coordination of the heme group to an asparagine residue (H193N), as well as converting a second histidine to an alanine residue (H73A) for comparison purposes. We employed spectral analysis and CO measurement by gas chromatography to analyze catalysis by ChuS, H193N, and H73A, demonstrating that His-193 is the key residue for the heme-degrading activity of ChuS.

PubMed: 17023414
DOI: 10.1074/JBC.M607684200

実験手法

X-RAY DIFFRACTION (1.45 Å)