FIGURE 1.

Detection of GspSSPs in E. coli. A, a schematic diagramming how Gsp S-thiolation of E. coli proteins was detected. ¹⁴C-Labeled spermidine (Spd*) was added into an E. coli culture and was then conjugated with GSH by Gsp synthetase activity in GspSA to form radiolabeled Gsp (Gsp*). Gsp*SSPs were detected by phosphorimaging after SDS-PAGE. The levels of radiolabeled proteins were reduced when extracts were treated with 2-ME. B, SDS-PAGE analysis of E. coli proteins in NR754 (wild type) and HA61002 (ΔgspSA). Left, Coomassie Brilliant Blue-stained proteins. Right, phosphorimaging of radiolabeled proteins.