clk-1 cDNA with an added 6-HIS tag was cloned into the pET-17bplasmid and further transfected into Rosetta TM (DE3) competent cells for protein expression. CLK-1-6-HIS was expressed in pET-17b cells on a large scale and subsequently purified using Ni-NTA Agarose beads (Qiagen 30210). Purified CLK-1-6-HIS was then sent to CoCalico Biologicals for injection into rabbits. clk-1