Orthogonal Site-Specific Dual Bioconjugation of Aryl and Alkyl Thiols.

ABSTRACT: We introduce aryl thiols as nucleophiles for site-specific protein and antibody bioconjugation, which allows the orthogonal labeling of native cysteines for double modification strategies. In a high-yielding synthesis, we introduce aromatic thiol substituents in two amino acids (4-SH-L-Phe and 3-SH-L-Tyr), which can be site-specifically incorporated into the C-terminus of a protein using the enzyme tubulin tyrosine ligase (TTL, Tub-tag labeling). In particular, we found that 3-SH-L-tyrosine shows excellent water solubility and incorporation rates, similar to previously described Tyr-derivatives. 2D NMR experiments revealed a pK_a value of 5.5 for the aryl thiol modality of 3-SH-L-tyrosine, which matches the pH-dependent reactivity

SUBMITTER: de Geus MAR 

PROVIDER: S-EPMC12147148 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature