Site-specific chemical modification of recombinant proteins produced in mammalian cells by using the genetically encoded aldehyde tag

Peng Wu, Wenqing Shui, Brian L. Carlson, Nancy Hu, David Rabuka, Julia Lee, Carolyn R. Bertozzi

Research output: Contribution to journalArticle

167 Scopus citations


The properties of therapeutic proteins can be enhanced by chemical modification. Methods for site-specific protein conjugation are critical to such efforts. Here, we demonstrate that recombinant proteins expressed in mammalian cells can be site-specifically modified by using a genetically encoded aldehyde tag. We introduced the peptide sequence recognized by the endoplasmic reticulum (ER)-resident formylglycine generating enzyme (FGE), which can be as short as 6 residues, into heterologous proteins expressed in mammalian cells. Cotranslational modification of the proteins by FGE produced products bearing a unique aldehyde group. Proteins bearing this "aldehyde tag" were chemically modified by selective reaction with hydrazide- or aminooxy-functionalized reagents. We applied the technique to site-specific modification of monoclonal antibodies, the fastest growing class of biopharmaceuticals, as well as membrane-associated and cytosolic proteins expressed in mammalian cells.

Original languageEnglish (US)
Pages (from-to)3000-3005
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number9
StatePublished - Mar 3 2009



  • Antibody engineering
  • Bioorthogonal reaction

ASJC Scopus subject areas

  • General

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