High resolution X-ray structures of the oxidised and reduced forms of nitrite reductase from Rhodobacter sphaeroides 2.4.3
Artikel i vetenskaplig tidskrift, 2005

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.

Rhodobacter sphaeroides

chemistry

Copper

Crystallography

metabolism

Protein Conformation

Hydrogen-Ion Concentration

X-Ray

Nitrite Reductases

enzymology

chemistry

Oxidation-Reduction

Författare

Frida Jacobson

Chalmers, Kemi- och bioteknik, Molekylär bioteknik

K Guo

AstraZeneca AB

Kenneth Olesen

Göteborgs universitet

M. Ökvist

Göteborgs universitet

Richard Neutze

Chalmers, Kemi- och bioteknik, Molekylär bioteknik

Lennart Sjölin

Göteborgs universitet

Acta Crystallographica Section D: Biological Crystallography

0907-4449 (ISSN) 1399-0047 (eISSN)

Vol. 61 9 1190-1198

Ämneskategorier

Biokemi och molekylärbiologi

DOI

10.1107/S0907444905017488