Site-specific covalent labeling of His-tag fused proteins with N-acyl-N-alkyl sulfonamide reagent

Vikram Thimaradka, Jae Hoon Oh, Christina Heroven, A. Radu Aricescu, Michisuke Yuzaki, Tomonori Tamura, Itaru Hamachi

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The ability to incorporate a desired functionality into proteins of interest in a site-specific manner can provide powerful tools for investigating biological systems and creating therapeutic conjugates. However, there are not any universal methods that can be applied to all proteins, and it is thus important to explore the chemical strategy for protein modification. In this paper, we developed a new reactive peptide tag/probe pair system for site-specific covalent protein labeling. This method relies on the recognition-driven reaction of a peptide tag and a molecular probe, which comprises the lysine-containing short histidine tag (KH6 or H6K) and a binuclear nickel (II)- nitrilotriacetic acid (Ni2+-NTA) complex probe containing a lysine-reactive N-acyl-N-alkyl sulfonamide (NASA) group. The selective interaction of the His-tag and Ni2+–NTA propeles a rapid nucleophilic reaction between a lysine residue of the tag and the electrophilic NASA group of the probe by the proximity effect, resulting in the tag-site-specific functionalization of proteins. We characterized the reactive profile and site-specificity of this method using model peptides and proteins in vitro, and demonstrated the general utility for production of a nanobody-chemical probe conjugate without compromising its binding ability.

Original languageEnglish
Article number115947
JournalBioorganic and Medicinal Chemistry
Publication statusPublished - 2021 Jan 15

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry


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