Prokaryotic Expression, Purification and Activity Detection of Phosphodiesterase 2A Protein

Abstract

Depression is associated with changes in cyclic guanosine monophosphate (cGMP) levels. Depression can be improved by increasing the cGMP concentration through the cGMP/PKG pathway with PDE2A inhibitors. This study is aimed to improve the expression of a highly active PDE2A protein with an Escherichia coli vector ST6 for the screening of PDE2A inhibitors. PDE2A gene was obtained through polymerase chain reaction. A recombinant plasmid of ST6-PDE2A was built by seamless cloning and then introduced into E. coli BL21 (DE3). The cultivation conditions were optimized to increase target protein expression. The expressed protein was purified with Ni-NTA affinity chromatography. Its purified activity was measured by a PDE-GloTM phosphodiesterase kit. An maximized protein expression was obtained by cultivating E. coli BL21 with ST6-PDE2A in the YT medium at 37 °C till OD600 reached to 0.6-0.8 and then by inducible expressing with 1 mM IPTG at 16 °C for 40 hours. The resultant active protein has an EC50 of 0.1196 mg/ml.