Fig. 2: Selectivity of bioconjugation with vinyl thianthrenium salts.
From: Chemoselective umpolung of thiols to episulfoniums for cysteine bioconjugation
a, Three-dimensional representation of the average 1H and 13C NMR shift perturbations of each amino acid after functionalization of 13C,15N-labelled ubiquitin T12C and the NOESY correlation plot of scaled cross-peak heights before and after functionalization of ubiquitin T12C. The linear regression of the experimental data is indicated as a solid line. b, Mean number of modified residues in E. coli lysate resulting from reaction with VTT/VTFT and sodium azide at different pH values. Data are derived from two technical replicates. TCEP was used for 1 h pre-reduction at 37 °C. c, Reactivity of DHAR1 mutants with VTT and N-methylmaleimide (NMM) and enzyme assay subsequent to the modification. The data are expressed as mean ± s.e. of nine independent experiments. The statistical analysis was performed via a two-sided analysis of variance, followed by post hoc Tukey test with P < 0.05 (see Supplementary Tables 11 and 12 for exact P values). The following publicly available protein structures were used: ubiquitin (PDB:1D3Z) and DHAR1 (PDB:5EL8).
