Cyclic 5-membered disulfides are not selective substrates of thioredoxin reductase, but are opened nonspecifically

• DOI: 10.1038/s41467-022-29136-4
• Publication Date: 2022-04-01T10:22:14Z
• Authors: Jan G. Felber; Lena Poczka; Karoline C. Scholzen; Lukas Zeisel; Martin S. Maier; Sander Busker; Ulrike Theisen; Christina Brandst...; Katja Becker; Elias S. J. Arnér; Julia Thorn-Seshold; Oliver Thorn-Seshold
• Keywords: Thiol; Glutaredoxin; Chemical Biology; Bioconjugation

The cyclic five-membered disulfide 1,2-dithiolane has been widely used in chemical biology and redox probes. Contradictory reports have described it either as nonspecifically reduced cells, or else a highly specific substrate for thioredoxin reductase (TrxR). Here we show that probes, such "TRFS" are by thiol reductants redox-active proteins, their cellular performance is barely affected TrxR inhibition knockout. Therefore, results of imaging inhibitor screening using 1,2-dithiolanes should not be interpreted reflecting activity, previous studies may need re-evaluation. To understand 1,2-dithiolanes' complex behaviour, probe localisation, environment-dependent fluorescence, reduction-independent ring-opening polymerisation, thiol-dependent uptake must all considered; particular caution needed when co-applying thiophilic inhibitors. We present general approach controlling against assay misinterpretation with reducible to ensure future TrxR-targeted designs robustly evaluated selectivity, better orient research.