ABSTRACT
Denaturation of proteins plays a crucial part in cellular activities. In this study, we have investigated the folding unfolding pathways of zebrafish dihydrofolate reductase (zDHFR) in presence of different chemical denaturants which were found to be an influential factor for the refolding yield by UV-visible spectrophotometric analysis. The activity change of zDHFR has been observed in presence of three different denaturants like Acetic Acid (AcOH), Sodium Dodecyl Sulphate (SDS), and Ethanol (C2H5OH). Spectrophotometric analysis reveals that protein unfolded completely at different concentrations and times by these denaturants. The spontaneous refolding experiments of chemically denatured zDHFR were also conducted to verify the spontaneous refolding yield. These investigations have helped us to decipher a picture about the denaturants contributing to achieving the refolding yield. We observed that acetic acid is a stronger denaturant among all, and the spontaneous refolding yields were higher from SDS denaturation. In the light of the above findings, higher spontaneous refolding yields were obtained from the low concentration of denaturants.
ABSTRACT
The recombinant plasmid of mChlL-18 prokaryotic expression was transformed into E.coli BL21(DE3) strain and then induced by IPTG at 37℃.After crushed and washed,the expressing inclusion bodies were thoroughly denatured with 6 mol/L guanidine hydrochloride.Then according to experiment design,the effects of rChlL-18 protein refolding yield at different densities were investigated by the systems of artificial chapercne at different densities.Experiment results indicate that there is a optimal condition on assiting rChIL-18 protein by using the artificial chaperone technique.The optimal condition can improve the refolding yield of rChIL-18 protein,and then the expressed product of fusion chicken IL-18 gene in E.coli has a relativity high bioactivity.