Nonmodified Strategy Enabled Proteome-Wide Mapping of Catechol Derivatives Interactome

Profiling
the interactome of catechol derivatives plays a key role
in revealing their pharmacology. Existing approaches for target identification
generally rely on either the modification of ligands or significant
perturbation of protein properties, which may restrict the coverage
of interacting proteins. Here, we present a modification-free strategy,
termed oxidative addition-boronate affinity enrichment (OABA), that
employed catechol oxidation to ortho-quinones to
covalently capture nucleophilic residues of proteins, followed by
selective enrichment via boronate affinity recognition of the catechol
moiety. This redox-enabled approach eliminated the requirement for
drug molecule modification while enabling direct mapping of catechol-protein
interactomes in living cells. Proof-of-concept studies with isoproterenol
(ISO) achieved a 2-fold enrichment of SOD1-adduct peptides from the
HeLa peptide mixture. Application to quercetin in live HeLa cells
identified 74 high-confidence interacting targets, enriched in biological
process linked to the modulation of protein stabilization, energy
metabolism, and cell growth. Through molecular docking and CETSA profiling,
we validated the interaction of FDPS, CCT7, and CS with quercetin.
Collectively, the OABA provided a reliable, modification-free platform
for mapping the native interactome of catechol-containing compounds
and advancing the understanding of polyphenolic pharmacology.