FIG. 4.

Overexpression (A) and circular dichroism analysis (B) of recombinant AnkB proteins. (A) E. coli BL21(λDE3) harboring pET23-ankB-480 was grown aerobically in L broth to mid-logarithmic phase and treated with 1 mM IPTG for 3 h at 37°C. After Ni²⁺-nitrilotriacetic acid purification, purified protein was separated by sodium dodecyl sulfate–12% polyacrylamide gel electrophoresis and the gel was stained with Coomassie blue R-250. Lane 1, molecular mass standard; lane 2, 15 μg of AnkB-480. (B) Circular dichroism spectrum of AnkB-480, using 100 μg ml⁻¹ in 10 mM sodium phosphate (pH 7.0) at 23°C.