1NIC

THE STRUCTURE OF CU-NITRITE REDUCTASE FROM ACHROMOBACTER CYCLOCLASTES AT FIVE PH VALUES, WITH NITRITE BOUND AND WITH TYPE II CU DEPLETED

Summary for 1NIC

• Entry DOI: 10.2210/pdb1nic/pdb
• Related: 1NIA 1NIB 1NID 1NIE 1NIF 2NRD
• Descriptor: NITRITE REDUCTASE, COPPER (II) ION, SULFATE ION, ... (4 entities in total)
• Functional Keywords: oxidoreductase (nitric oxide(a))
• Biological source: Achromobacter cycloclastes
• Cellular location: Periplasm: P25006
• Total number of polymer chains: 1
• Total formula weight: 37282.96

Authors

Adman, E.T.,Godden, J.W.,Turley, S. (deposition date: 1995-07-03, release date: 1995-12-07, Last modification date: 2024-02-14)

Primary citation

Adman, E.T.,Godden, J.W.,Turley, S.
The structure of copper-nitrite reductase from Achromobacter cycloclastes at five pH values, with NO2- bound and with type II copper depleted.
J.Biol.Chem., 270:27458-27474, 1995

PubMed Abstract: High resolution x-ray crystallographic structures of nitrite reductase from Achromobacter cycloclastes, undertaken in order to understand the pH optimum of the reaction with nitrite, show that at pH 5.0, 5.4, 6.0, 6.2, and 6.8, no significant changes occur, other than in the occupancy of the type II copper at the active site. An extensive network of hydrogen bonds, both within and between subunits of the trimer, maintains the rigidity of the protein structure. A water occupies a site approximately 1.5 A from the site of the type II copper in the structure of the type II copper-depleted structure (at pH 5.4), again with no other significant changes in structure. In nitrite-soaked crystals, nitrite binds via its oxygens to the type II copper and replaces the water normally bound to the type II copper. The active-site cavity of the protein is distinctly hydrophobic on one side and hydrophilic on the other, providing a possible path for diffusion of the product NO. Asp-98 exhibits thermal parameter values higher than its surroundings, suggesting a role in shuttling the two protons necessary for the overall reaction. The strong structural homology with cupredoxins is described.

PubMed: 7499203
DOI: 10.1074/jbc.270.46.27458

Experimental method

X-RAY DIFFRACTION (1.9 Å)