Expression, Purification, and Bioactivity of a Soluble Recombinant Ovine Interferon-tau in Escherichia Coli

Enhancing high-efficient cadmium biosorption of Escherichia coli via cell surface displaying metallothionien CUP1

Cadmium (Cd) is one of the common heavy metal pollutants in soil, which can induce various diseases and pose a serious threat to human health. Metallothioneins (MTs) are well-known for their excellent metal binding ability due to a high content of cysteine, which has great potential for heavy metal chelation. In this study, we used the Escherichia coli (E. coli) surface display system LPP-OmpA to construct a recombinant plasmid pBSD-LCF encoding LPP-OmpA-CUP1-Flag fusion protein. Then we displayed the metallothionein CUP1 from Saccharomyces cerevisiae on E. coli DH5α surface for Cd removing. The feasibility of surface display of metallothionein CUP1 in recombinant E. coli DH5α (pBSD-LCF) by Lpp-OmpA system was proved by flow cytometry and western blot analysis, and the specificity of the fusion protein in the recombinant strain was also verified. The results showed that the Cd2+ resistance capacity of DH5α (pBSD-LCF) was highly enhanced by about 200%. Fourier-transform infrared spectroscopy showed that sulfhydryl and sulfonyl groups were involved in Cd2+ binding to cell surface of DH5α (pBSD-LCF). Meanwhile, Cd removal rate by DH5α (pBSD-LCF) was promoted to 95.2%. Thus, the recombinant strain E. coli DH5α (pBSD-LCF) can effectively chelate environmental metals, and the cell surface expression of metallothionein on E. coli can provide new ideas and directions for heavy metals remediation.

Cloning and prokaryotic expression of WRKY48 from Caragana intermedia

Caragana intermedia (C. intermedia) is a kind of drought-tolerant leguminous shrub. WRKY transcription factors are one of the largest family of transcription factors in plants and play critical regulatory roles in stress tolerance and the development of plants. In our study, CiWRKY48 was cloned from C. intermedia, analyzed using bioinformatics software, and expressed with a prokaryotic expression system. The results showed that the open reading frame (ORF) of CiWRKY48 was 1158bp, the molecular weight (MW) was 42 kDa, and its subcellular localization was in the nucleus. Additionally, fusion protein was obtained, and confirmed by western blotting. The stress resistance of the pET30a-His-MBP-CiWRKY48 transformed Escherichia coli expression strain was reduced under mannitol and salt treatment, compared with the control. Overall, our findings provided a foundation for uncovering the function of CiWRKY48.