A single-chain antibody fragment is functionally expressed in the cytoplasm of both Escherichia coli and transgenic plants

Paraskevi Tavladoraki, Alessandra Girotti, Marcello Donini, Francisco Javier Arias, Camillo Mancini, Veronica Morea, Roberta Chiaraluce, Valerio Consalvi, Eugenio Benvenuto

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Despite the well-known crucial role of intradomain disulfide bridges for immunoglobulin folding and stability, the single-chain variable fragment of the anti-viral antibody F8 is functionally expressed when targeted to the reducing environment of the plant cytoplasm. We show here that this antibody fragment is also functionally expressed in the cytoplasm of Escherichia coli. A gel shift assay revealed that the single-chain variable fragment (scFv) accumulating in the plant and bacterial cytoplasm bears free sulfhydryl groups. Guanidinium chloride denaturation/renaturation studies indicated that refolding occurs even in a reducing environment, producing a functional molecule with the same spectral properties of the native scFv(F8). Taken together, these results suggest that folding and functionality of this antibody fragment are not prevented in a reducing environment. This antibody fragment could therefore represent a suitable framework for engineering recombinant antibodies to be targeted to the cytoplasm.
Original languageEnglish
Pages (from-to)617 - 624
Number of pages8
JournalEuropean Journal of Biochemistry
Issue number2
Publication statusPublished - 1 Jun 1999
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Biochemistry

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