Purification of recombinant bovine normal prion protein PrP(104-242) by HPHIC

Purification of the prion protein (PrP) is a major concern for biological or biophysical analysis as are the structural specificities of this protein in relation to infectivity. A simple and efficient method for purification of recombinant bovine normal prion protein containing residues 104-242, PrP(104-242) expressed in Escherichia coli by high performance hydrophobic interaction chromatography (HPHIC) was presented in this work. The solution containing denatured and reduced protein in 8.0 mol/L urea extracted from the inclusion body was directly injected into the HPHIC column, aggregates were prevented by the interaction between the denatured PrP(104-242) molecules and the stationary phase during the chromatographic process, the soluble form of PrP(104-242) in aqueous solution was obtained after desorbed from the column. Several factors, including pH value, types of stationary phase and salt, and gradient mode, influencing the purification results were investigated. Optimal conditions were obtained for the purification of PrP(104-242) by HPHIC. This procedure yield PrP(104-242) of a purity of 96% with a recovery of 87%, respectively, for a single step purification of 40 min.