Figure 1.

Rationale and strategy for studying the role of redox partner tethering in copper containing nitrite reductase. (A) Structure (in complex with Ax cytochrome c₅₅₁; PDB ID 2ZON; top) and proposed mechanism (bottom) of prototypic 2-domain AxNiR. (B) Structure (PDB ID: 3ZIY; top) and proposed mechanism (bottom) of the 3-domain copper containing nitrite reductase, RpNiR, used in this study. In (A) and (B), the three monomers in the structure of the trimeric CuNiRs are shown as green, magenta, and cyan. The isolated cyt c₅₅₁ protein is shown in yellow. (C) Strategy of dissecting the 3-domain cytochrome c-tethered Ralstonia pickettii copper nitrite reductase into the component domains. In the schematic shown in (C), the three monomers in the structure of RpNiR are shown as green, magenta, and cyan. The isolated RpNiR cyt c protein is shown in yellow.