Summary for 4CDP
| Entry DOI | 10.2210/pdb4cdp/pdb |
| Descriptor | PUTATIVE HEME/HEMOGLOBIN TRANSPORT PROTEIN, FORMIC ACID, PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total) |
| Functional Keywords | heme degradation, structural repeat, montreal- kingston bacterial structural genomics initiative, bsgi, oxidoreductase |
| Biological source | ESCHERICHIA COLI |
| Total number of polymer chains | 1 |
| Total formula weight | 41487.41 |
| Authors | Suits, M.D.L.,Jaffer, N.,Jia, Z. (deposition date: 2013-11-05, release date: 2013-11-13, Last modification date: 2023-12-20) |
| Primary citation | 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 Cited by 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: 17023414DOI: 10.1074/JBC.M607684200 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.45 Å) |
Structure validation
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