EspA is a novel fusion partner for expression of foreign proteins in Escherichia coli

Yan Cheng, Jiang Gu, Hai guang Wang, Shu Yu, Yan qing Liu, Ya lei Ning, Quan ming Zou, Xue jie Yu, Xu hu Mao

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


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 languageEnglish (US)
Pages (from-to)380-388
Number of pages9
JournalJournal of Biotechnology
Issue number3
StatePublished - Nov 2010
Externally publishedYes


  • Escherichia coli
  • EspA
  • Fusion partner
  • Fusion protein

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Applied Microbiology and Biotechnology


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