http://www.cnr.it/ontology/cnr/individuo/prodotto/ID11579
The O2-scavenging flavodiiron protein in the human parasite Giardia intestinalis. (Articolo in rivista)
- Type
- Label
- The O2-scavenging flavodiiron protein in the human parasite Giardia intestinalis. (Articolo in rivista) (literal)
- Anno
- 2008-01-01T00:00:00+01:00 (literal)
- Alternative label
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
- Di Matteo A; Scandurra FM; Testa F; Forte E; Sarti P; Brunori M; Giuffrè A (literal)
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- Pagina fine
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
- Rivista
- Note
- ISI Web of Science (WOS) (literal)
- Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
- Department of Biochemical Sciences, CNR Institute of Molecular Biology and Pathology and Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza, University of Rome, Rome I-00185, Italy. (literal)
- Titolo
- The O2-scavenging flavodiiron protein in the human parasite Giardia intestinalis. (literal)
- Abstract
- 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 O2-reductase activity (>40 s-?1), but very low NO-reductase activity (?0.2 s?-1); O2 reacts with the reduced protein
quite rapidly (milliseconds) and with high affinity (Km < 2 u?M), producing H2O. 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 nonheme 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 scavengeO2, allowing this microaerobic parasite to survive in the human small intestine,
thus promoting its pathogenicity. (literal)
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- Autore CNR
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