Replacement of trifluoroacetic acid with HCl in the hydrophobic purification steps of pediocin PA-1: a structural effect.

ABSTRACT

Trifluoroacetic acid (TFA) is a purification contaminant associated with pediocin PA-1 that interferes with Fourier transform infrared spectroscopy structural analysis. As revealed by circular dichroism, its presence affects the structural folding of pediocin. Consequently, we propose a new pediocin PA-1 purification procedure using HCl instead of TFA in all of the hydrophobic steps. This procedural change does not affect the purification yield or the amount of pediocin PA-1 purified. Furthermore, removing HCl, as opposed to TFA, after purification is an easier procedure to carry out. In fact, the removal of TFA requires more experimentation and results in protein loss. Thus, HCl is a good alternative to TFA in pediocin PA-1 purification and can be extended to the purification of other proteins. We also show that TFA-induced structural modifications do not significantly affect the antimicrobial activity of pediocin PA-1.