Structures of the oxidized and reduced forms of nitrite reductase fromRhodobacter sphaeroides2.4.3 at high pH: changes in the interactions of the type 2 copper
| Autor: | Lennart Sjölin, Kenneth Olesen, Hongwei Guo, Richard Neutze, Frida Jacobson, Mats Ökvist |
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| Rok vydání: | 2005 |
| Předmět: |
Nitrite Reductases
Denitrification biology Protein Conformation Denitrification pathway chemistry.chemical_element Trimer Rhodobacter sphaeroides General Medicine Hydrogen-Ion Concentration Crystallography X-Ray biology.organism_classification Nitrite reductase Photochemistry Copper Nitric oxide chemistry.chemical_compound chemistry Structural Biology Nitrite Oxidation-Reduction |
| Zdroj: | Acta Crystallographica Section D Biological Crystallography. 61:1190-1198 |
| ISSN: | 0907-4449 |
| DOI: | 10.1107/s0907444905017488 |
| Popis: | Nitrite reductase is an enzyme operating in the denitrification pathway which catalyses the conversion of nitrite (NO2(-)) to gaseous nitric oxide (NO). Here, crystal structures of the oxidized and reduced forms of the copper-containing nitrite reductase from Rhodobacter sphaeroides 2.4.3 are presented at 1.74 and 1.85 A resolution, respectively. Whereas the structure of the enzyme is very similar to those of other copper-containing nitrite reductases, folding as a trimer and containing two copper sites per monomer, the structures reported here enable conformational differences between the oxidized and reduced forms of the enzyme to be identified. In the type 1 copper site, a rotational perturbation of the side chain of the copper ligand Met182 occurs upon reduction. At the type 2 copper site, a dual conformation of the catalytic residue His287 is observed in the oxidized structure but is lacking in the reduced structure, such that the interactions of the oxidized type 2 copper ion can be regarded as adopting octahedral geometry. These findings shed light on the structural mechanism of the reduction of a copper-bound nitrite to nitric oxide and water. |
| Databáze: | OpenAIRE |
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