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Figure 2
Structural organization of TsNirK. (a) Homotrimer viewed from different angles. The two-domain NirK core structure is attached to the extra C-terminal domain arrangement (right panel). A diagram of the distribution of domains along the sequence is shown at the bottom. (b) Ribbon diagram of a monomer with domain I (blue) containing T1CuN and T2Cu, domain II (green), domain III (purple) harbouring the T1CuC centre, the linker loop (red) between domains I and II and the long loop (orange) between domain II and III. (c) Distribution and coordination spheres of each copper centre. The representation of T1CuN–T2Cu connections: Cys115–His114 bridge and the Ser78CAT-containing sensing loop (His75 to His80). (d) Proton-channel electron-transfer-coupled pathway. The coulombic coloured surface shows the possible structural contact area with physiological mediators.

IUCrJ
Volume 6| Part 2| March 2019| Pages 248-258
ISSN: 2052-2525
https://doi.org/10.1107/S2052252519000241