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Figure 2
Structural and biophysical characterization of MhGgH. (a) Cartoon representation of the overall structure of the MhGgH monomer. The (α/α)6 domain is coloured mauve, and the A′- and B′-­regions are coloured salmon and blue, respectively. The N- and C-termini are indicated in yellow boxes. The views in the left and right panels are related by a 90° rotation around x. (b) Analytical size-exclusion chromatogram of tagged (dotted line) and tag-less (solid line) MhGgH variants. The standards used for column calibration (see Section 2[link]) are indicated as inverted black triangles. (c) Analysis of tagged (dotted line) and tag-less (solid line) MhGgH variants by DLS. The tag-less variant displayed a larger hydro­dynamic radius (Rh = 7.34 nm) and a lower polydispersity index (PdI = 0.092) than the tagged MhGgH variant (Rh = 5.75 nm; PdI = 0.201). (d) Melting temperatures of MhGgH variants determined by differential scanning fluorimetry, highlighting the lower stability of the tagged MhGgH variant. Error bars correspond to standard deviations. (e) Quaternary structure of MhGgH. Monomers are coloured green (molecule A), wheat (molecule B), cyan (molecule C) and blue (molecule D). The A:B and A:C interfaces are indicated. The glycerol and serine molecules found in the active-site region are represented by salmon spheres. The approximate dimensions of the homotetramer are indicated. The views on the left and right are related by a 90° rotation around y. (f) Superposition of the experimental SAXS data (dotted grey line) and the theoretical SAXS curve calculated from the tetrameric crystallographic model of MhGgH (solid black line).

IUCrJ
Volume 6| Part 4| July 2019| Pages 572-585
ISSN: 2052-2525
https://doi.org/10.1107/S2052252519005372