RIEDL tag: A novel pentapeptide tagging system for transmembrane protein purification

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Affinity tag systems are an essential tool in biochemistry, biophysics, and molecular biology. Although several different tag systems have been developed, the epitope tag system, composed of a polypeptide “tag” and an anti-tag antibody, is especially useful for protein purification. However, almost all tag sequences, such as the FLAG tag, are added to the N- or C-termini of target proteins, as tags inserted in loops tend to disrupt the functional structure of multi-pass transmembrane proteins. In this study, we developed a novel “RIEDL tag system,” which is composed of a peptide with only five amino acids (RIEDL) and an anti-RIEDL monoclonal antibody (mAb), LpMab-7. To investigate whether the RIEDL tag system is applicable for protein purification, we conducted the purification of two kinds of RIEDL-tagged proteins using affinity column chromatography: whale podoplanin (wPDPN) with an N-terminal RIEDL tag (RIEDL-wPDPN) and human CD20 with an internal RIEDL tag insertion (CD20-169RIEDL170). Using an LpMab-7-Sepharose column, RIEDL-wPDPN and CD20-169RIEDL170 were efficiently purified in one-step purification procedures, and were strongly detected by LpMab-7 using Western blot and flow cytometry. These results show that the RIEDL tag system can be useful for the detection and one-step purification of membrane proteins when inserted at either the N-terminus or inserted in an internal loop structure of multi-pass transmembrane proteins.

Original languageEnglish
Article number100780
JournalBiochemistry and Biophysics Reports
Publication statusPublished - 2020 Sep


  • CD20
  • Monoclonal antibody
  • Peptide tag
  • Podoplanin
  • Protein purification
  • RIEDL tag

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry

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