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Figure 4
NO2−-bound T2Cu site of AcNiR. (a) NO2− is bound to the T2Cu in two conformations in the SF-ROXNIT structure: top-hat and side-on conformations with equal occupancy (50% each). Asp98 is visible in both proximal and gatekeeper conformations, with the gatekeeper conformation corresponding to the top-hat NO2− in the SF-ROXNIT structure. (b) Conformation of nitrite at pH 5.0 obtained using a low-dose home source. (c) At pH 6.5 only a single side-on conformation is visible corresponding to a single Asp98 (AspCAT) proximal position. The half-occupancy water molecule is also bound to T2Cu in the same conformation as in the SF-ROXOX structure. 2Fo − Fc electron density is contoured at the 1σ level and is shown as a grey mesh. Atoms are coloured by element, with different colour schemes used for the different chains. The T2Cu is shown as a cyan sphere and water molecules are shown as small red spheres. Metal-coordinating bonds are shown as red dotted lines. Selected hydrogen bonds are shown as black dotted lines.

IUCrJ
Volume 6| Part 4| July 2019| Pages 761-772
ISSN: 2052-2525
https://doi.org/10.1107/S2052252519008285