Conjugation of a reactive thiol at the nucleotide binding site for site-specific antibody functionalization

Nathan J. Alves, Nur Mustafaoglu, Basar Bilgicer

Research output: Contribution to journalArticle

12 Scopus citations


Described here is a UV photo-cross-linking method that utilizes the NBS (nucleotide binding site) for site-specific covalent functionalization of antibodies with reactive thiol moieties (UV-NBSThiol), while preserving antibody activity. By synthesizing an indole-3-butyric acid (IBA) conjugated version of cysteine we site-specifically photo-cross-linked a reactive thiol moiety to antibodies at the NBS. This thiol moiety can then be used as an orthogonally reactive location to conjugate various types of functional ligands that possess a thiol reactive group through disulfide bond formation or reaction with a maleimide functionalized ligand. Our results demonstrate the utility of the UV-NBSThiol method by successfully functionalizing a prostate specific antigen antibody (IgGPSA) with IBA-Thiol and subsequent reaction with maleimide-fluorescein. An optimal UV energy of 0.5-1.5 J/cm2 was determined to yield the most efficient photo-cross-linking and resulted in 1-1.5 conjugations per antibody while preserving antibody/antigen binding activity and Fc recognition. Utilizing the IBA-Thiol ligand allows for an efficient means of site-specifically conjugating UV sensitive functionalities to antibody NBS that would otherwise not have been amenable by the previously described UV-NBS photo-cross-linking method. The UV-NBSThiol conjugation strategy can be utilized in various diagnostic and therapeutic applications with nearly limitless potential for the preparation of site-specific covalent conjugation of affinity tags, fluorescent molecules, peptides, and chemotherapeutics to antibodies.

Original languageEnglish (US)
Pages (from-to)1198-1202
Number of pages5
JournalBioconjugate Chemistry
Issue number7
StatePublished - Jul 16 2014
Externally publishedYes

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry

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