2q9u

Crystal structure of the flavodiiron protein from Giardia intestinalis

spinqualitylabelsall models 2q9u, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2q9u is a 2 chain structure with sequence from Giardia intestinalis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: FEO, FMN, NO3 Gene: fprA (Giardia intestinalis) Resources: FirstGlance, OCA, RCSB, PDBsum 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 The flavodiiron proteins (FDP) are widespread among strict or facultative anaerobic prokaryotes, where they are involved in the response to nitrosative and/or oxidative stress. Unexpectedly, FDPs were fairly recently identified in a restricted group of microaerobic protozoa, including Giardia intestinalis, the causative agent of the human infectious disease giardiasis. The FDP from Giardia was expressed, purified, and extensively characterized by x-ray crystallography, stopped-flow spectroscopy, respirometry, and NO amperometry. Contrary to flavorubredoxin, the FDP from Escherichia coli, the enzyme from Giardia has high O(2)-reductase activity (>40 s(-1)), but very low NO-reductase activity (approximately 0.2 s(-1)); O(2) reacts with the reduced protein quite rapidly (milliseconds) and with high affinity (K(m) < or = 2 microM), producing H(2)O. The three-dimensional structure of the oxidized protein determined at 1.9A resolution shows remarkable similarities with prokaryotic FDPs. Consistent with HPLC analysis, the enzyme is a dimer of dimers with FMN and the non-heme di-iron site topologically close at the monomer-monomer interface. Unlike the FDP from Desulfovibrio gigas, the residue His-90 is a ligand of the di-iron site, in contrast with the proposal that ligation of this histidine is crucial for a preferential specificity for NO. We propose that in G. intestinalis the primary function of FDP is to efficiently scavenge O(2), allowing this microaerobic parasite to survive in the human small intestine, thus promoting its pathogenicity. The O2-scavenging flavodiiron protein in the human parasite Giardia intestinalis.,Di Matteo A, Scandurra FM, Testa F, Forte E, Sarti P, Brunori M, Giuffre A J Biol Chem. 2008 Feb 15;283(7):4061-8. Epub 2007 Dec 12. PMID:18077462 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Flavodoxin

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