Enzyme-mediated site-specific bioconjugation of metal complexes to proteins: Sortase-mediated coupling of copper-64 to a single-chain antibody

Brett M Paterson, Karen Maria Alt, Charmaine M Jeffery, Roger I Price, Schweta Jagdale, Charlotte Claire Williams, Sheena Rigby, Karlheinz Peter, Christoph Eugen Hagemeyer, Paul Stephen Donnelly

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The enzyme-mediated site-specific bioconjugation of a radioactive metal complex to a single-chain antibody using the transpeptidase sortase A is reported. Cage amine sarcophagine ligands that were designed to function as substrates for the sortase A mediated bioconjugation to antibodies were synthesized and enzymatically conjugated to a single-chain variable fragment. The antibody fragment scFvanti-LIBS targets ligand-induced binding sites (LIBS) on the glycoprotein receptor GPIIb/IIIa, which is present on activated platelets. The immunoconjugates were radiolabeled with the positron-emitting isotope 64Cu. The new radiolabeled conjugates were shown to bind selectively to activated platelets. The diagnostic potential of the most promising conjugate was demonstrated in an in vivo model of carotid artery thrombosis using positron emission tomography. This approach gives homogeneous products through site-specific enzyme-mediated conjugation and should be broadly applicable to other metal complexes and proteins.
Original languageEnglish
Pages (from-to)6115-6119
Number of pages5
JournalAngewandte Chemie - International Edition
Issue number24
Publication statusPublished - 2014
Externally publishedYes

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