Fukuda and Inoue  have determined the crystal structure of the C135A mutant of thermostable copper nitrite reductase (CuNIR) from Geobacillus thermodenitrificans in complex with nitrite to 1.55 Å resolution. Interestingly, this high-temperature (320 K) structure  displays a near-bidentate binding mode of nitrite distinct from a monodentate mode in a cryogenic structure :
To our knowledge, this is the first case in which the difference in substrate binding modes between cryogenic and high-temperature structures has been visualized by crystallography.The copper site geometries are given in Table 1.
Table 1 (adapted from )
|Cu—Ligand Distances (Å)||3X1N (320 K)||3WKP (100 K)|
|I. Type 1 Cu—residue distances|
|II. Type 2 Cu—residue distances|
|III. Type 2 Cu—nitrite distances|
- Fukuda, Y. and Inoue, T. (2015) High-temperature and high-resolution crystallography of thermostable copper nitrite reductase. Chemical Communications 51, 6532—6535.
- Fukuda, Y. and Inoue, T. (2015) High-temperature and high-resolution crystallography of thermostable copper nitrite reductase. Electronic Supplementary Material.