Addition of an N-Terminal Poly-Glutamate Fusion Tag Improves Solubility and Production of Recombinant TAT-Cre Recombinase in Escherichia coli

A. Hyeon Kim, Soohyun Lee, Suwon Jeon, Goon Tae Kim, Eun Jig Lee, Daham Kim, Younggyu Kim, Tae Sik Park

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1 Citation (Scopus)


Cre recombinase is widely used to manipulate DNA sequences for both in vitro and in vivo research. Attachment of a trans-activator of transcription (TAT) sequence to Cre allows TATCre to penetrate the cell membrane, and the addition of a nuclear localization signal (NLS) helps the enzyme to translocate into the nucleus. Since the yield of recombinant TAT-Cre is limited by formation of inclusion bodies, we hypothesized that the positively charged arginine-rich TAT sequence causes the inclusion body formation, whereas its neutralization by the addition of a negatively charged sequence improves solubility of the protein. To prove this, we neutralized the positively charged TAT sequence by proximally attaching a negatively charged poly-glutamate (E12) sequence. We found that the E12 tag improved the solubility and yield of E12-TAT-NLS-Cre (E12-TAT-Cre) compared with those of TAT-NLS-Cre (TATCre) when expressed in E. coli. Furthermore, the growth of cells expressing E12-TAT-Cre was increased compared with that of the cells expressing TAT-Cre. Efficacy of the purified TATCre was confirmed by a recombination test on a floxed plasmid in a cell-free system and 293 FT cells. Taken together, our results suggest that attachment of the E12 sequence to TAT-Cre improves its solubility during expression in E. coli (possibly by neutralizing the ionic-charge effects of the TAT sequence) and consequently increases the yield. This method can be applied to the production of transducible proteins for research and therapeutic purposes.

Original languageEnglish
Pages (from-to)109-117
Number of pages9
JournalJournal of microbiology and biotechnology
Issue number1
Publication statusPublished - 2020 Jan 28

Bibliographical note

Funding Information:
This research was supported by the Gachon University research fund of 2019 (GCU-2019-0315) and the Bio & Medical Technology Development Program through the National Research Foundation of Korea (NRF), funded by the Korean government (MSIP) (NRF-2014M3A9B6069338, 2018M3A9F3020970) to T.S.P.

Publisher Copyright:
© 2020 by The Korean Society for Microbiology and Biotechnology.

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Applied Microbiology and Biotechnology


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