1as6: Difference between revisions
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==Overview== | ==Overview== | ||
The structures of oxidized, reduced, nitrite-soaked oxidized and | The structures of oxidized, reduced, nitrite-soaked oxidized and nitrite-soaked reduced nitrite reductase from Alcaligenes faecalis have been determined at 1.8-2.0 A resolution using data collected at -160 degrees C. The active site at cryogenic temperature, as at room temperature, contains a tetrahedral type II copper site liganded by three histidines and a water molecule. The solvent site is empty when crystals are reduced with ascorbate. A fully occupied oxygen-coordinate nitrite occupies the solvent site in crystals soaked in nitrite. Ascorbate-reduced crystals soaked in a glycerol-methanol solution and nitrite at -40 degrees C remain colorless at -160 degrees C but turn amber-brown when warmed, suggesting that NO is released. Nitrite is found at one-half occupancy. Five new solvent sites in the oxidized nitrite bound form exhibit defined but different occupancies in the other three forms. These results support a previously proposed mechanism by which nitrite is bound primarily by a single oxygen atom that is protonable, and after reduction and cleavage of that N-O bond, NO is released leaving the oxygen atom bound to the Cu site as hydroxide or water. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Alcaligenes faecalis]] | [[Category: Alcaligenes faecalis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Transferred entry: 1 | [[Category: Transferred entry: 1 7.2 1]] | ||
[[Category: Adman, E | [[Category: Adman, E T.]] | ||
[[Category: Murphy, M | [[Category: Murphy, M E.P.]] | ||
[[Category: Turley, S.]] | [[Category: Turley, S.]] | ||
[[Category: CU]] | [[Category: CU]] | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:47:45 2008'' | ||
Revision as of 12:47, 21 February 2008
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STRUCTURE OF NITRITE BOUND TO OXIDIZED ALCALIGENES FAECALIS NITRITE REDUCTASE AT CRYO TEMPERATURE
OverviewOverview
The structures of oxidized, reduced, nitrite-soaked oxidized and nitrite-soaked reduced nitrite reductase from Alcaligenes faecalis have been determined at 1.8-2.0 A resolution using data collected at -160 degrees C. The active site at cryogenic temperature, as at room temperature, contains a tetrahedral type II copper site liganded by three histidines and a water molecule. The solvent site is empty when crystals are reduced with ascorbate. A fully occupied oxygen-coordinate nitrite occupies the solvent site in crystals soaked in nitrite. Ascorbate-reduced crystals soaked in a glycerol-methanol solution and nitrite at -40 degrees C remain colorless at -160 degrees C but turn amber-brown when warmed, suggesting that NO is released. Nitrite is found at one-half occupancy. Five new solvent sites in the oxidized nitrite bound form exhibit defined but different occupancies in the other three forms. These results support a previously proposed mechanism by which nitrite is bound primarily by a single oxygen atom that is protonable, and after reduction and cleavage of that N-O bond, NO is released leaving the oxygen atom bound to the Cu site as hydroxide or water.
About this StructureAbout this Structure
1AS6 is a Single protein structure of sequence from Alcaligenes faecalis with and as ligands. Active as Transferred entry: 1.7.2.1, with EC number 1.7.99.3 Known structural/functional Sites: , , , , and . Full crystallographic information is available from OCA.
ReferenceReference
Structure of nitrite bound to copper-containing nitrite reductase from Alcaligenes faecalis. Mechanistic implications., Murphy ME, Turley S, Adman ET, J Biol Chem. 1997 Nov 7;272(45):28455-60. PMID:9353305
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