Vandenberghe I H, Meyer T E, Cusanovich M A, Van Beeumen J J
Laboratorium voor Eiwitbiochemie en Eiwitengineering, University of Gent, Belgium.
Biochem Biophys Res Commun. 1998 Jun 29;247(3):734-40. doi: 10.1006/bbrc.1998.8847.
The complete amino acid sequence of the blue copper-containing nitrite reductase enzyme (NiR) from Achromobacter xylosoxidans has been determined by chemical analysis, supported by high precision mass analysis. The polypeptide chain contains 336 residues with an overall charge of 0, including the +2 state of each of the copper ions. The two NiR enzymes for which the three-dimensional structures have been solved are green in color and have different absorption spectra than those of the blue-colored protein from A. xylosoxidans. The ligands to the two copper atoms are conserved. Therefore, the difference between the blue and the green NiR must depend on subtle changes in the geometry of the type I copper-sulfur bond. Both overall protein charge and active site charge are different in A. xylosoxidans NiR which may reflect the use of azurin as electron donor as opposed to the other enzymes that use pseudoazurin.
木糖氧化无色杆菌含蓝色铜的亚硝酸还原酶（NiR）的完整氨基酸序列已通过化学分析确定，并得到高精度质谱分析的支持。多肽链包含336个残基，总电荷为0，其中包括每个铜离子的+2价态。已解析三维结构的两种NiR酶呈绿色，其吸收光谱与木糖氧化无色杆菌的蓝色蛋白质不同。两个铜原子的配体是保守的。因此，蓝色和绿色NiR之间的差异必定取决于I型铜硫键几何结构的细微变化。木糖氧化无色杆菌NiR的整体蛋白质电荷和活性位点电荷均不同，这可能反映出与使用假天青蛋白的其他酶相反，该酶使用天青蛋白作为电子供体。
