3hyw

3-D X-Ray structure of the sulfide:quinone oxidoreductase of the hyperthermophilic bacterium Aquifex aeolicus in complex with decylubiquinone

spinqualitylabelsall models 3hyw, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3hyw is a 6 chain structure with sequence from Aquifex aeolicus. This structure supersedes the now removed PDB entry 3h28. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: CSS, DCQ, FAD, H2S, LMT, PS9, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SQRD_AQUAE Catalyzes the oxidation of hydrogen sulfide, with the help of a quinone. Consecutive reaction cycles lead to the accumulation of a polysulfide product on the active site Cys residues; these products are released when they exceed a critical length, typically as cyclooctasulfur. 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 Sulfide:quinone oxidoreductase (SQR) is a flavoprotein with homologues in all domains of life except plants. It plays a physiological role both in sulfide detoxification and in energy transduction. We isolated the protein from native membranes of the hyperthermophilic bacterium Aquifex aeolicus, and we determined its X-ray structure in the "as-purified," substrate-bound, and inhibitor-bound forms at resolutions of 2.3, 2.0, and 2.9 A, respectively. The structure is composed of 2 Rossmann domains and 1 attachment domain, with an overall monomeric architecture typical of disulfide oxidoreductase flavoproteins. A. aeolicus SQR is a surprisingly trimeric, periplasmic integral monotopic membrane protein that inserts about 12 A into the lipidic bilayer through an amphipathic helix-turn-helix tripodal motif. The quinone is located in a channel that extends from the si side of the FAD to the membrane. The quinone ring is sandwiched between the conserved amino acids Phe-385 and Ile-346, and it is possibly protonated upon reduction via Glu-318 and/or neighboring water molecules. Sulfide polymerization occurs on the re side of FAD, where the invariant Cys-156 and Cys-347 appear to be covalently bound to polysulfur fragments. The structure suggests that FAD is covalently linked to the polypeptide in an unusual way, via a disulfide bridge between the 8-methyl group and Cys-124. The applicability of this disulfide bridge for transferring electrons from sulfide to FAD, 2 mechanisms for sulfide polymerization and channeling of the substrate, S(2-), and of the product, S(n), in and out of the active site are discussed. The structure of Aquifex aeolicus sulfide:quinone oxidoreductase, a basis to understand sulfide detoxification and respiration.,Marcia M, Ermler U, Peng G, Michel H Proc Natl Acad Sci U S A. 2009 Jun 1. PMID:19487671 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Quinone reductase 3D structures

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