Scalable purification and characterization of the extracellular domain of human autotaxin from prokaryotic cells

Autotaxin (ATX) is an approximately 125 kDa transmembrane protein known as a tumor progression factor based on its lysophospholipase D (lysoPLD) activity. There are many reports of the biological and biochemical properties of ATX, but crystallographic or structural studies have not been reported because a large-scale production process using prokaryotic cells has not been established.Here we report a bulk purification process and soluble expression of the recombinant human ATX (rhATX S48) from prokaryotic cells. The extracellular domain of human ATX cDNA was cloned into a pET101/D-TOPO vector and transformed to an Escherichia coliBL21 strain which was co-transformed with a pTF16 chaperone plasmid. The rhATX S48 was purified with chaperone and it was removed by Mg2+-ATP treatment. The final yield of purified rhATX S48 was approximately 3.5 mg/l culture of recombinant strain. The rhATX S48 shows lysoPLD enzymatic activity and effectively stimulates the growth and motile activity of the human tumor cells as well as native ATX.This is a first report for scalable purification of the ATX molecule and the rhATX S48 should be a good tool for immunization of anti-ATX or crystallographic analysis of ATX.