A Versatile Heteroatom Nucleophile Hub enabling divergent Thiol and Amine Bioconjugate Synthesis

Bioconjugates have widespread applications in biologically relevant fields and are typically synthesized through the coupling of naturally abundant nucleophiles, such as thiol and amine groups. Consequently, various chemoselective crosslinking reagents for specific nucleophiles have been developed to generate desired bioconjugates. Motivated by the limited nucleophile compatibility of current reagents, we report 1,4-difluoro-2,5-dinitrobenzene (p-DFDNB) as a unified crosslinking reagent that serves as a versatile heteroatom nucleophile hub (VHNH), enabling divergent bioconjugation via sequential chemo- and regio-specific nucleophilic aromatic substitution (SNAr) reactions with thiol and amine nucleophiles, yielding thiol–thiol, amine–amine, and amine–thiol bioconjugates. The VHNH is compatible with a broad range of thiol- and amine-containing substrates, including small molecules, pharmaceuticals, biomolecules, and functional tags. Furthermore, this approach enables the construction of a series of post-translationally modified proteins bearing diverse functional tags. Overall, the VHNH strategy offers a facile and versatile platform for constructing a wide variety of bioconjugates.