Figure 2.

Structural analysis of wild-type gal-7 and the R74S mutant. (A) Superimposed ¹H-¹⁵N HSQC spectra of wild-type (green) and R74S (red) gal-7 at 310 K and 800 MHz. (B) ¹H-¹⁵N chemical shift differences Δδ (ppm) caused by the R74S mutation mapped on the primary sequence of gal-7. The ¹H-¹⁵N weighted average composite chemical shift differences (Δδ) were calculated between WT and variant R74S according to the following equation [17]: Δδ (ppm) = [(Δδ² _HN + Δδ² _N/25)/2]^½. (C) Three-dimensional structure of gal-7 showing the general β-sheet topology of the carbohydrate recognition domain (CRD) and the position of the carbohydrate binding site, as delineated by residues H49, N51, R53, N62, W69, E72 and R74. (D) Mapping of ¹H-¹⁵N chemical shift variations (Δδ) between wtgal-7 and variant R74S on the 3D structure of gal-7 [PDB: 3ZXF]. Residues with chemical shift variations Δδ >0.05 ppm are plotted on the structure of gal-7 (in blue). The position of the R74 residue is shown in purple. (E) Immunoblots showing soluble monomeric and dimeric forms of recombinant gal-7 in a native gel.