title: High yields and soluble expression of superoxide dismutases in Escherichia coli due to the HIV-1 Tat peptide via increases in mRNA transcription.
abstract: This study aimed to validate the high yield and soluble expression of proteins carrying the transactivator of transcription (Tat) peptide tag, and further explored the potential mechanism by which the Tat tag increases expression. Escherichia coli superoxide dismutase (SOD) proteins, including SodA, SodB and SodC, were selected for analysis. As expected, the yields and the solubility of Tat-tagged proteins were higher than those of Tat-free proteins, and similar results were observed for the total SOD enzyme activity. Bacterial cells that overexpressed Tat-tagged proteins exhibited increased anti-paraquat activity compared with those expressing Tat-free proteins that manifested as SodA>SodC>SodB. When compared with an MG1655 wild-type strain, the growth of a ΔSodA mutant strain was found to be inhibited after paraquat treatment; the growth of ΔSodB and ΔSodC mutant strains was also slightly inhibited. The mRNA transcript level of genes encoding Tat-tagged proteins was higher than that of genes encoding Tat-free proteins. Furthermore, the α-helix and turn of Tat-tagged proteins were higher than those of Tat-free proteins, but the β-sheet and random coil content was lower. These results indicated that the incorporation of the Tat core peptide as a significant basic membrane transduction peptide in fusion proteins could increase mRNA transcripts and promote the high yield and soluble expression of heterologous proteins in E. coli.
authors.affiliation: Department of Biological Engineering, College of Pharmacy, Jilin University, Changchun, China.
authors.forename: Yangdong
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Beijing Institute of Radiation Medicine, State Key Laboratory of Proteomics, Cognitive and Mental Health Research Center, Beijing, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Ye
authors.affiliation: Institute of Protein Research, Tongji University, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Wu
authors.affiliation: Beijing Institute of Radiation Medicine, State Key Laboratory of Proteomics, Cognitive and Mental Health Research Center, Beijing, China.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Beijing Institute of Radiation Medicine, State Key Laboratory of Proteomics, Cognitive and Mental Health Research Center, Beijing, China.
authors.forename: Chenggang
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Biological Engineering, College of Pharmacy, Jilin University, Changchun, China.
authors.forename: Weiqun
authors.initials: W
authors.lastname: Yan
mesh_terms: D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D015497:HIV-1 / Q000235:genetics; D010269:Paraquat / Q000037:antagonists & inhibitors; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000235:genetics*; D012995:Solubility; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D012333:RNA, Messenger; D054322:tat Gene Products, Human Immunodeficiency Virus; D013482:Superoxide Dismutase; D010269:Paraquat