Fig. 3: Effects of FDX2 and FXN on persulfide generation, transfer and reduction.
From: Cross-regulation of [2Fe–2S] cluster synthesis by ferredoxin-2 and frataxin
a–c, Kinetic profiles measured by ARBS assays monitoring persulfide generation on NFS1 in the NFS1–apo-ISCU2 complex in the absence of FXN or in the presence of 10 eq. FXN (a), persulfide transfer from NFS1 to Fe–ISCU2 in the absence of FXN or in the presence of 1, 5 or 10 eq. FXN (b) and persulfide reduction on Fe–ISCU2 by a mixture containing FDX2, FDXR and NADPH in the absence of FXN or in the presence of 1 eq. or 10 eq. FXN (c). d, Kinetics of [2Fe–2S] cluster synthesis after persulfide transfer, monitored by UV-visible spectroscopy at 456 nm after pre-incubation of the (NIAU)2 complex with l-cysteine for 5 min in the presence of 1, 10, or 50 eq. FXN, and initiation of the assembly reaction by adding FDX2, FDXR and NADPH. e–h, Kinetic profiles of ARBS assays monitoring persulfide generation on NFS1 (top legend) or on NFS1 in the NFS1-apo-ISCU2 complex (bottom legend) in the absence of FDX2 or in the presence of 10 eq. FDX2 (e), persulfide transfer from pre-persulfidated NFS1 to Fe–ISCU2 in the absence of FDX2 or in the presence of 3, 5 or 10 eq. FDX2 (f), persulfide transfer from NFS1 to Fe–ISCU2 in the absence of FDX2 or in the presence of 1, 3, 5, 7, or 10 eq. FDX2 (g) and persulfide transfer from NFS1 to Fe–ISCU2 with 1 eq. FXN present and either in the absence of FDX2 or in the presence of 1 or 10 eq. FDX2 (h). The schemes above each panel describe the reactions between non-persulfidated (-SH) and persulfidated (-SSH) proteins. Kinetic profiles monitor percentage of persulfidated NFS1 (NFS1–SSH) (a,e) or persulfidated ISCU2 (ISCU2–SSH) (b,c,f–h). Data in a–c,e–h are mean ± s.d., n = 3 independent experiments; data in d are representative kinetics selected from n = 3 independent experiments with similar results.
