3hx9 | pdb_00003hx9

Structure of heme-degrader, MhuD (Rv3592), from Mycobacterium tuberculosis with two hemes bound in its active site

spinqualitylabelsall models 3hx9, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3hx9 is a 2 chain structure with sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.75Å Ligands: CL, HEM Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MHUD_MYCTU Catalyzes the oxidative degradation of the heme macrocyclic porphyrin ring in the presence of a suitable electron donor such as ascorbate or NADPH--cytochrome P450 reductase, with subsequent release of free iron. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Heme degradation plays a pivotal role in the availability of the essential nutrient, iron, in pathogenic bacteria. A previously unannotated protein from Mycobacterium tuberculosis, Rv3592, which shares homology to heme-degrading enzymes, has been identified. Biochemical analyses confirm that Rv3592, which we have termed MhuD (mycobacterial heme utilization, degrader), is able to bind and degrade heme. Interestingly, contrary to previously reported stoichiometry for the Staphylococcus aureus heme degraders, iron-regulated surface determinant (Isd)G and IsdI, MhuD has the ability to bind heme in a 1:2 protein-to-heme ratio, although the MhuD-diheme complex is inactive. Furthermore, the 1.75-A crystal structure of the MhuD-diheme complex reveals two stacked hemes forming extensive contacts with residues in the active site. In particular, the solvent-exposed heme is axially liganded by His75 and is stacked planar upon the solvent-protected heme. The solvent-protected heme is coordinated by a chloride ion, which is, in turn, stabilized by Asn7. Structural comparison between MhuD-diheme and inactive IsdG and IsdI bound to only one highly distorted metalloporphyrin ring reveals that several residues located in alpha-helix 2 and the subsequent loop appear to be responsible for heme stoichiometric differences and suggest open and closed conformations for substrate entry and product exit. Unusual diheme conformation of the heme-degrading protein from Mycobacterium tuberculosis.,Chim N, Iniguez A, Nguyen TQ, Goulding CW J Mol Biol. 2010 Jan 22;395(3):595-608. Epub 2009 Nov 14. PMID:19917297 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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