Use of a HEHEHE purification tag instead of a hexahistidine tag improves biodistribution of affibody molecules site-specifically labeled with 99mTc, 111In, and 125I

Camilla Hofström, Anna Orlova, Mohamed Altai, Fredrik Wangsell, Torbjörn Gräslund, Vladimir Tolmachev

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

Affibody molecules are a class of small (̃7 kDa) robust scaffold proteins suitable for radionuclide molecular imaging in vivo. The attachment of a hexahistidine (His6)-tag to the Affibody molecule allows facile purification by immobilized metal ion affinity chromatography (IMAC) but leads to high accumulation of radioactivity in the liver. Earlier, we have demonstrated that replacement of the His6-tag with the negatively charged histidine-glutamate-histidine-glutamate-histidine-glutamate (HEHEHE)-tag permits purification of Affibody molecules by IMAC, enables labeling with [ 99mTc(CO)3]+, and provides low hepatic accumulation of radioactivity. In this study, we compared the biodistribution of cysteine-containing Affibody molecules site-specifically labeled with 111In, 99mTc, and 125I at the C-terminus, having a His6-tag at the N- or C-terminus or a HEHEHE-tag at the N-terminus. We show that the use of a HEHEHEtag provides appreciable reduction of hepatic radioactivity, especially for radiometal labels. We hope that this information can also be useful for development of other scaffold protein-based imaging agents.

Original languageEnglish
Pages (from-to)3817-3826
Number of pages10
JournalJournal of Medicinal Chemistry
Volume54
Issue number11
DOIs
Publication statusPublished - 9 Jun 2011
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Medicine
  • Drug Discovery

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