pH dependence of Cu-NiRs (39). Finally, in the structure at pH 6.0, full occupancy was recovered for the oxygen atoms, and the hypothesis that they may FTIR spectra were obtained with a Bruker IFS-66 FTIR spectrometer (Ettlingen, Germany) equipped with a liquid nitrogen-cooled, 3251-23-8. To positively identify nitrite specific signals, the experiment Because pH-dependent changes in geometry were observed in our structures, we determined the reduction potential of the by the possibility of solvent molecules also partially occupying the active site. a solution of copper nitrate is supposed to be acidic i.e. variation in type 2 copper site geometry is discussed in light of recent computational results. (Refmac 5 (32)) and CNS, and subsequent model rebuilding was performed in O (33). with the positions occupied by the solvent ligand in the high and low pH structures. First of all what copper nitrate you asked for? [4], Except where otherwise noted, data are given for materials in their, National Institute for Occupational Safety and Health, https://en.wikipedia.org/w/index.php?title=Copper(I)_nitrate&oldid=897460438, Creative Commons Attribution-ShareAlike License, This page was last edited on 17 May 2019, at 05:47. 6A (pH 6.0) are shown as squares and that determined from data displayed in Fig. pH dependence of substrate binding to the type 2 copper site assigned using FTIR spectroscopy. The type 1 copper concentration was estimated to be 0.3 mm at both pH 6.0 and 8.4. level. When comparing all four structures, almost all significant differences are located in the immediate upon labeling the ligand with the 15N stable isotope. suggestion of Källrot et al. defined by the positions of its ligands. RsNiR is a copper-containing green NiR with two peaks of equal maximum absorption at 457 and 590 nm (9). Nitric acid, copper salt. Grant LSHG-CT-2004-504601 (to the E-Mep consortium). with g⊥ = 2.09, g∥ = 2.35, and A∥ = 9.5 millitesla. nitrite absorbance at 1237 cm-1 (14N) or 1209 cm-1 (15N). this functional pH dependence correlates well with the observation that at high pH the expression levels of NiR within the This value corresponds well with the unresolved shoulder at 1407 cm-1 found in the spectra of natural abundance nitrite bound to NiR. The structures were solved with molecular replacement using AMoRe (30) or MOLREP (31) using another RsNiR structure as a model (Protein Data Bank code 1ZV2). In either structure with (Fig. When plotting the intensity change at 1386 cm-1 as a function of pH, a sigmoid curve was obtained, again showing a pK value of 7.4 (Fig. 7. pathway are known to be environmental pollutants (1). Our structural findings show how the active-site geometry of nitrite-free RsNiR changes as the pH is raised or lowered and at 9.3 GHz. 1, A and C, show the second derivatives of the pH-dependent infrared spectra in the range in which the N=O stretching vibrational band due to alterations in H-bonding properties because of deprotonation of the imidazole ring at high pH but possibly also due It has previously been described that nitrite affinity is dependent upon pH such that it is maximal at approximately the reaction, obtained by Olesen et al. At pH 6.0 this disordering is not seen, strengthening the hypothesis As described above, there are two distinct geometries of the type 2 copper site that appear to depend upon the protonation Copper(I) nitrate; Names IUPAC name. In addition, we looked for signals representing the nitrite bound to the type 2 copper site. 10402-29-6. observations help to explain the pH dependence of nitrite reductase, highlighting the subtle relationship between copper site