Relative position of the hexahistidine tag effects binding properties of a tumor-associated single-chain Fv construct

Apollina Goel, David Colcher, Ja Seok Koo, Barbara J.M. Booth, Gabriela Pavlinkova, Surinder K. Batra

Research output: Contribution to journalArticlepeer-review

82 Scopus citations

Abstract

Hexahistidine tag (His-tag) is the most widely used tag for affinity purification of recombinant proteins for their structural and functional analysis. In the present study, single chain Fv (scFv) constructs were engineered form the monoclonal antibody (MAb) CC49 which is among the most extensively studied MAb for cancer therapy. For achieving efficient purification of scFvs by immobilized metal-ion affinity chromatography (IMAC), a His-tag was placed either at the C-terminal (scFv-His6) or N- terminal (His6-scFv) of the coding sequence. Solid-phase radioimmunoassay for scFv-His6 showed only 20-25% binding whereas both His6-scFv and scFv (no His-tag) showed 60-65% binding. Surface plasmon resonance studies by BIAcore revealed the binding affinity constant (K(A)) for His6-scFv and scFv as 1.19 x 106 M-1 and 3.27 x 106 M-1, respectively. No K(A) value could be calculated for scFv-His6 due to poor binding kinetics (k(on) and k(off)). Comparative homology modeling for scFv and scFv-His6 showed that the C- terminal position of the His-tag partially covered the antigen-binding site of the protein. The study demonstrates that the C-terminal position of His- tag on the CC49 scFv adversely affects the binding properties of the construct. The results emphasize the importance of functional characterization of recombinant proteins expressed with purification tags. (C) 2000 Elsevier Science B.V.

Original languageEnglish (US)
Pages (from-to)13-20
Number of pages8
JournalBiochimica et Biophysica Acta - General Subjects
Volume1523
Issue number1
DOIs
StatePublished - Sep 1 2000

Keywords

  • BIAcore
  • Histidine tag
  • Immobilized metal affinity chromatography
  • Single chain Fv
  • Yeast

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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