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Figure 2
β3 domain-swapped structure of m-cGrx1. (a) Overall tetrameric structure of m-cGrx1. The disulfide dimers of m-cGrx1 are shown in beige (subunits A and C) and the domain-swapped dimers of m-cGrx1 are shown in purple and blue (subunits B and D). The red arrow indicates an intermolecular disulfide bridge between subunits A and B. (b) The domain-swapped m-cGrx1 monomers exchange β3, β4 and α3 with one another and are linked by a hinge loop. (c) The β3 domain-swapped m-cGrx1 structure (blue) reveals that the tertiary structure is unwound compared with that of d-cGrx1 (beige) and that the hinge loop is located between α2 and β3. (d) Comparison of the catalytic cysteine (Cys13) between domain-swapped m-cGrx1 and d-cGrx1. The superimposed domain-swapped m-cGrx1 (blue) and d-cGrx1 (beige) show that the catalytic cysteines (Cys13) are oriented differently. A disulfide dimeric m-cGrx1 is shown in gray. A 2Fo − Fc electron-density map is shown at the disulfide bridge. The domain-swapped m-cGrx1 (blue) and disulfide dimeric m-cGrx1 form a disulfide bridge. The 2Fo − Fc electron-density map is shown at 2.0σ.

IUCrJ
Volume 7| Part 6| November 2020| Pages 1019-1027
ISSN: 2052-2525
https://doi.org/10.1107/S2052252520011598