Fig. 3. Formation of NsrR-bound RRE species. (A) Structures of the NsrR [4Fe–4S] cluster and proposed RRE and persulfide RRE species, where Cys is derived from the protein. (B) Formation of [Fe2(NO)4] adduct in the absence (grey circles) or presence of GSH (yellow squares), MSH (red squares) or ergothioneine (green squares). (C–F) LC-MS spectra of [4Fe–4S] NsrR following additions of NO in (C) the absence and presence of (D) glutathione (GSH), (E) ergothioneine, and (F) mycothiol (MSH). Samples were maintained under anaerobic conditions prior to LC-MS analysis. The data correspond to multiple repeats (n ≥ 2); error bars represent SEM.
