Preparation of recombinant six-histidine-tagged human LECT2, a chemotactic protein to neutrophils, in Escherichia coli.

LECT2 is a chemotactic protein to neutrophils. A recombinant six-histidine-tagged human LECT2, (His)(6)-LECT2, was expressed in E. coli using a pET21a(+) vector. The (His)(6)-LECT2 was purified from the soluble fraction in E. coli as a single band in sodium dodesyl sulfate/polyacrylamide gel electrophoresis using three steps of column chromatography with Ni(2+)-charged nitrilo-triacetic acid (Ni-NTA) agarose, DEAE-Sepharose, and CM-Sepharose. The purified (His)(6)-LECT2 was yielded with 96 µg from the soluble fraction of 1,500 ml culture of E. coli. The circular dichroism spectrum of (His)(6)-LECT2 showed the folded structure, which is rich in β-sheet structure and rare in α-helix.