*3.2. Expression and Purification of edG*

We successfully transformed the edG gene, expressed it into the BL23 (DE3) strain of *E. coli* and purified the protein with some modifications described earlier [30,66,67]. Briefly, the protein was expressed by induction with 0.5 mM IPTG for 12 h at 30 ◦C. The inclusion bodies (IBs) were prepared, and the protein was purified by Ni-NTA chromatography. The bound protein was eluted with 50 mM Tris buffer (pH 8.0), 100 mM NaCl, 5% glycerol, 0.5% N-lauroylsarcosine, and 150 mM Imidazole. The eluted fractions were analyzed and confirmed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The eluted fraction with the desired single band was dialyzed against 20 mM Tris buffer (pH 7.5) and 100 mM NaCl. The dialysis buffer was consecutively changed five times at 4 ◦C with stirring for 24 h to get the refolded protein. The protein concentration was

measured using a molar absorbance coefficient of 8730 M−<sup>1</sup> cm−<sup>1</sup> by Jasco V-600 UV-visible spectrophotometer at 280 nm [68].
