4KNU

Copper nitrite reductase from Nitrosomonas europaea at pH 6.5

Summary for 4KNU

• Entry DOI: 10.2210/pdb4knu/pdb
• Related: 4KNS 4KNT
• Descriptor: Multicopper oxidase type 1, COPPER (II) ION, GLYCEROL, ... (5 entities in total)
• Functional Keywords: nitrite reductase, oxidoreductase
• Biological source: Nitrosomonas europaea
• Total number of polymer chains: 6
• Total formula weight: 190491.91

Authors

Rosenzweig, A.C.,Lawton, T.L.,Sayavedra-Soto, L.A.,Arp, D.J. (deposition date: 2013-05-10, release date: 2013-07-24, Last modification date: 2024-02-28)

Primary citation

Lawton, T.J.,Bowen, K.E.,Sayavedra-Soto, L.A.,Arp, D.J.,Rosenzweig, A.C.
Characterization of a nitrite reductase involved in nitrifier denitrification.
J.Biol.Chem., 288:25575-25583, 2013

PubMed Abstract: Nitrifier denitrification is the conversion of nitrite to nitrous oxide by ammonia-oxidizing organisms. This process, which is distinct from denitrification, is active under aerobic conditions in the model nitrifier Nitrosomonas europaea. The central enzyme of the nitrifier dentrification pathway is a copper nitrite reductase (CuNIR). To understand how a CuNIR, typically inactivated by oxygen, functions in this pathway, the enzyme isolated directly from N. europaea (NeNIR) was biochemically and structurally characterized. NeNIR reduces nitrite at a similar rate to other CuNIRs but appears to be oxygen tolerant. Crystal structures of oxidized and reduced NeNIR reveal a substrate channel to the active site that is much more restricted than channels in typical CuNIRs. In addition, there is a second fully hydrated channel leading to the active site that likely acts a water exit pathway. The structure is minimally affected by changes in pH. Taken together, these findings provide insight into the molecular basis for NeNIR oxygen tolerance.

PubMed: 23857587
DOI: 10.1074/jbc.M113.484543

Experimental method

X-RAY DIFFRACTION (1.8 Å)