Abstract
Escherichia coli secreted protein A (EspA) is a component of the type 3 secretion system (T3SS). The high level of expression when self-stimulated suggests that EspA may be used as a fusion partner. In the present study, EspA was used as a "fusion partner" to construct a fusion expression system, pEspA, in order to improve the expression and solubility of proteins from prokaryotes and eukaryotes. Target proteins were linked to the C-terminus of EspA by a linker containing a YAPQDP sequence, multiple cloning sites and an enterkinase cleavage site. Six proteins, IL-24, Stx2A1, Stx2B, S1, IntiminC300 and GFP, were expressed as EspA-fusion proteins using this vector. The expression level of each protein was enhanced by EspA and the majority of them (Stx2B, IntiminC300, GFP, Stx2A1, IL-24) were expressed in soluble form. EspA-fusion proteins can be purified by affinity chromatography (Sepharose chelated with EspA-specific monoclonal antibody) and by Ni2+ affinity chromatography for they contain a 6× His tag at their C-terminus. In addition, IL-24 remains soluble and demonstrates certain anti-tumor activity after the removal of EspA by enterkinase. The EspA fusion expression system was efficient in enhancing expression levels and the solubility of target proteins.
Original language | English (US) |
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Pages (from-to) | 380-388 |
Number of pages | 9 |
Journal | Journal of Biotechnology |
Volume | 150 |
Issue number | 3 |
DOIs | |
State | Published - Nov 2010 |
Externally published | Yes |
Keywords
- Escherichia coli
- EspA
- Fusion partner
- Fusion protein
ASJC Scopus subject areas
- Biotechnology
- Bioengineering
- Applied Microbiology and Biotechnology