The application of ELP[I]50 tag for recombinant thioredoxin purification and PEG on the influence of the inverse temperature transition

Abstract:

[Objective] To use the self-designed ELP[I]50 as the non-chromatographic purification tag, the recombinant Trx was purified, and the inverse temperature transition (Tt) of ELP[I]50-Trx influenced by PEG was investigated. [Methods] The Trx gene was synthesised, and was subcloned into the modified pET28-ELP expression vector, and the expression vector was transformed into BLR(DE3). The fusion protein was expressed and purified via inverse transition cycling (ITC), then the Tt was tested under different concentration of PEG. [Results] ELP[I]50-Trx fusion protein was successfully expressed and purifid via ITC, Tt was 28.6 °C when ELP[I]50-Trx is 25 μmol/L; the Tt was reduced down to 22.3 °C, 15.9 °C, 6 °C and 0 °C when PEG concentrations is 5%, 10%, 15%, 20% respective. [Conclusion] The ELP[I]50 can perform as an efficient recombinate protein purification tag to scale up at low cost and easy to use, and PEG can reduce protein Tt to enhance the purification efficiency for enlarging the range of application. ELP could be applied to a variety of recombinant proteins purification.