1nib
From Proteopedia
THE STRUCTURE OF CU-NITRITE REDUCTASE FROM ACHROMOBACTER CYCLOCLASTES AT FIVE PH VALUES, WITH NITRITE BOUND AND WITH TYPE II CU DEPLETED
Overview
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.
About this Structure
1NIB is a Single protein structure of sequence from Achromobacter cycloclastes. Full crystallographic information is available from OCA.
Reference
The structure of copper-nitrite reductase from Achromobacter cycloclastes at five pH values, with NO2- bound and with type II copper depleted., Adman ET, Godden JW, Turley S, J Biol Chem. 1995 Nov 17;270(46):27458-74. PMID:7499203 Page seeded by OCA on Sat May 3 02:34:12 2008
