Efficient expression of aquaporin Z in Escherichia coli cell-free system using different fusion vectors

Aquaporin z (aqpz) is a typical orthodox aquaporin with 6 transmembrane domains and five connecting loops. in order to express this complex membrane protein efficiently,e. coli cell-free expression system was employed as an alternative to produce aquaporin z. using different fusion vectors containing aqpz gene,the expression level of fusion proteins in cell-free system varied from 7.97 to 578.35 μg/ml,while 7.34 to 340.81 μg/ml for target protein (aqpz). the free energy of mrna secondary structure at translation initiation region (tir) was predicted and demonstrated a positive relationship with the expression level of aqpz in cell-free system. this is the first report of expressing water channel protein in e. coli cell-free system,which has become a highly promising tool for fast and efficient production of integral membrane proteins. © 2010 bentham science publishers ltd.