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Figure 5
Conformation of residues in the primary proton channel and T2Cu site of wtRpNiR, as-isolated and NO-soaked Gln262Asn RpNiR mutant structures. (A) wtRpNiR channel. (B) The water-filled channel in as-isolated Gln262Asn RpNiR. (C) Electron transfer route of NO-soaked Gln262Asn from the haem to T1Cu, and T2Cu; (D) In NO-soaked Gln262Asn RpNiR, two states of Gln262Asn can be observed. The details of the interaction of residues in state 1 are shown in (E) and in state 2 in (F). For simplicity, Tyr131 is only shown when it is involved in the water-network-related interactions. Small red spheres represent water molecules, the black dashed lines are the hydrogen bonds, the red dashed lines are the interactions involving T2Cu and the deep blue sphere is T2Cu. Gln262Asn RpNiR is shown in magenta and orange. The 2Fo − Fc electron-density map is contoured at the 1σ level and shown as a grey mesh.

IUCrJ
Volume 13| Part 4| July 2026|
ISSN: 2052-2525
https://doi.org/10.1107/S2052252526004549