2ppf: Difference between revisions
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|PDB= 2ppf |SIZE=350|CAPTION= <scene name='initialview01'>2ppf</scene>, resolution 1.65Å | |PDB= 2ppf |SIZE=350|CAPTION= <scene name='initialview01'>2ppf</scene>, resolution 1.65Å | ||
|SITE= | |SITE= | ||
|LIGAND= <scene name='pdbligand= | |LIGAND= <scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CU:COPPER+(II)+ION'>CU</scene>, <scene name='pdbligand=CU1:COPPER+(I)+ION'>CU1</scene>, <scene name='pdbligand=NO:NITRIC+OXIDE'>NO</scene>, <scene name='pdbligand=TRS:2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL'>TRS</scene> | ||
|ACTIVITY= [http://en.wikipedia.org/wiki/Nitrite_reductase_(NO-forming) Nitrite reductase (NO-forming)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.2.1 1.7.2.1] | |ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Nitrite_reductase_(NO-forming) Nitrite reductase (NO-forming)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.2.1 1.7.2.1] </span> | ||
|GENE= nirK, nir ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=511 Alcaligenes faecalis]) | |GENE= nirK, nir ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=511 Alcaligenes faecalis]) | ||
|DOMAIN= | |||
|RELATEDENTRY=[[1j9r|1J9R]] | |||
|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2ppf FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2ppf OCA], [http://www.ebi.ac.uk/pdbsum/2ppf PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2ppf RCSB]</span> | |||
}} | }} | ||
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[[Category: Murphy, M E.P.]] | [[Category: Murphy, M E.P.]] | ||
[[Category: Tocheva, E I.]] | [[Category: Tocheva, E I.]] | ||
[[Category: bacteria]] | [[Category: bacteria]] | ||
[[Category: copper]] | [[Category: copper]] | ||
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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 Mon Mar 31 04:39:03 2008'' | ||
Revision as of 04:39, 31 March 2008
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| , resolution 1.65Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , , , | ||||||
| Gene: | nirK, nir (Alcaligenes faecalis) | ||||||
| Activity: | Nitrite reductase (NO-forming), with EC number 1.7.2.1 | ||||||
| Related: | 1J9R
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Reduced mutant D98N of AfNiR exposed to nitric oxide
OverviewOverview
Nitrite reductase (NiR) is an enzyme that uses type 1 and type 2 copper sites to reduce nitrite to nitric oxide during bacterial denitrification. A copper-nitrosyl intermediate is a proposed, yet poorly characterized feature of the NiR catalytic cycle. This intermediate is formally described as Cu(I)-NO+ and is proposed to be formed at the type 2 copper site after nitrite binding and electron transfer from the type 1 copper site. In this study, copper-nitrosyl complexes were formed by prolonged exposure of exogenous NO to crystals of wild-type and two variant forms of NiR from Alcaligenes faecalis (AfNiR), and the structures were determined to 1.8 A or better resolution. Exposing oxidized wild-type crystals to NO results in the reverse reaction and formation of nitrite that remains bound at the active site. In a type 1 copper site mutant (H145A) that is incapable of electron transfer to the type 2 site, the reverse reaction is not observed. Instead, in both oxidized and reduced H145A crystals, NO is observed bound in a side-on manner to the type 2 copper. In AfNiR, Asp98 forms hydrogen bonds to both substrate and product bound to the type 2 Cu. In the D98N variant, NO is bound side-on but is more disordered when observed for the wild-type enzyme. The solution EPR spectra of the crystallographically characterized NiR-NO complexes indicate the presence of an oxidized type 2 copper site and thus are interpreted as resulting from stable copper-nitrosyls and formally assigned as Cu(II)-NO-. A reaction scheme in which a second NO molecule is oxidized to nitrite can account for the formation of a Cu(II)-NO- species after exposure of the oxidized H145A variant to NO gas.
About this StructureAbout this Structure
2PPF is a Single protein structure of sequence from Alcaligenes faecalis. Full crystallographic information is available from OCA.
ReferenceReference
Stable copper-nitrosyl formation by nitrite reductase in either oxidation state., Tocheva EI, Rosell FI, Mauk AG, Murphy ME, Biochemistry. 2007 Oct 30;46(43):12366-74. Epub 2007 Oct 9. PMID:17924665
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