1w3o: Difference between revisions
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==Overview== | ==Overview== | ||
5-Nitroimidazole-based antibiotics are compounds extensively used for | 5-Nitroimidazole-based antibiotics are compounds extensively used for treating infections in humans and animals caused by several important pathogens. They are administered as prodrugs, and their activation depends upon an anaerobic 1-electron reduction of the nitro group by a reduction pathway in the cells. Bacterial resistance toward these drugs is thought to be caused by decreased drug uptake and/or an altered reduction efficiency. One class of resistant strains, identified in Bacteroides, has been shown to carry Nim genes (NimA, -B, -C, -D, and -E), which encode for reductases that convert the nitro group on the antibiotic into a non-bactericidal amine. In this paper, we have described the crystal structure of NimA from Deinococcus radiodurans (drNimA) at 1.6 A resolution. We have shown that drNimA is a homodimer in which each monomer adopts a beta-barrel fold. We have identified the catalytically important His-71 along with the cofactor pyruvate and antibiotic binding sites, all of which are found at the monomer-monomer interface. We have reported three additional crystal structures of drNimA, one in which the antibiotic metronidazole is bound to the protein, one with pyruvate covalently bound to His-71, and one with lactate covalently bound to His-71. Based on these structures, a reaction mechanism has been proposed in which the 2-electron reduction of the antibiotic prevents accumulation of the toxic nitro radical. This mechanism suggests that Nim proteins form a new class of reductases, conferring resistance against 5-nitroimidazole-based antibiotics. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Kapp, U.]] | [[Category: Kapp, U.]] | ||
[[Category: Kozielski-Stuhrmann, S.]] | [[Category: Kozielski-Stuhrmann, S.]] | ||
[[Category: Leiros, H | [[Category: Leiros, H K.S.]] | ||
[[Category: Leonard, G | [[Category: Leonard, G A.]] | ||
[[Category: Mcsweeney, S | [[Category: Mcsweeney, S M.]] | ||
[[Category: Terradot, L.]] | [[Category: Terradot, L.]] | ||
[[Category: ACT]] | [[Category: ACT]] | ||
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[[Category: nim gene]] | [[Category: nim gene]] | ||
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Revision as of 16:40, 21 February 2008
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CRYSTAL STRUCTURE OF NIMA FROM D. RADIODURANS
OverviewOverview
5-Nitroimidazole-based antibiotics are compounds extensively used for treating infections in humans and animals caused by several important pathogens. They are administered as prodrugs, and their activation depends upon an anaerobic 1-electron reduction of the nitro group by a reduction pathway in the cells. Bacterial resistance toward these drugs is thought to be caused by decreased drug uptake and/or an altered reduction efficiency. One class of resistant strains, identified in Bacteroides, has been shown to carry Nim genes (NimA, -B, -C, -D, and -E), which encode for reductases that convert the nitro group on the antibiotic into a non-bactericidal amine. In this paper, we have described the crystal structure of NimA from Deinococcus radiodurans (drNimA) at 1.6 A resolution. We have shown that drNimA is a homodimer in which each monomer adopts a beta-barrel fold. We have identified the catalytically important His-71 along with the cofactor pyruvate and antibiotic binding sites, all of which are found at the monomer-monomer interface. We have reported three additional crystal structures of drNimA, one in which the antibiotic metronidazole is bound to the protein, one with pyruvate covalently bound to His-71, and one with lactate covalently bound to His-71. Based on these structures, a reaction mechanism has been proposed in which the 2-electron reduction of the antibiotic prevents accumulation of the toxic nitro radical. This mechanism suggests that Nim proteins form a new class of reductases, conferring resistance against 5-nitroimidazole-based antibiotics.
About this StructureAbout this Structure
1W3O is a Single protein structure of sequence from Deinococcus radiodurans with and as ligands. Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of 5-nitroimidazole antibiotic resistance: the crystal structure of NimA from Deinococcus radiodurans., Leiros HK, Kozielski-Stuhrmann S, Kapp U, Terradot L, Leonard GA, McSweeney SM, J Biol Chem. 2004 Dec 31;279(53):55840-9. Epub 2004 Oct 18. PMID:15492014
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