YeeD is an essential partner for YeeE-mediated thiosulfate uptake in bacteria and regulates thiosulfate ion decomposition

by Mai Ikei, Ryoji Miyazaki, Keigo Monden, Yusuke Naito, Azusa Takeuchi, Yutaro S. Takahashi, Yoshiki Tanaka, Keina Murata, Takaharu Mori, Muneyoshi Ichikawa, Tomoya Tsukazaki Uptake of thiosulfate ions as an inorganic sulfur source from the environment is important for bacterial sulfur assimilation. Recently, a selective thiosulfate uptake pathway involving a membrane protein YeeE (TsuA) inEscherichia coli was characterized. YeeE-like proteins are conserved in some bacteria, archaea, and eukaryotes. However, the precise function of YeeE, along with its potential partner protein in the thiosulfate ion uptake pathway, remained unclear. Here, we assessed selective thiosulfate transport viaSpirochaeta thermophila YeeE in vitro and characterizedE.coli YeeD (TsuB) as an adjacent and essential protein for YeeE-mediated thiosulfate uptake in vivo. We further showed thatS.thermophila YeeD possesses thiosulfate decomposition activity and that a conserved cysteine in YeeD was modified to several forms in the presence of thiosulfate. Finally, the crystal structures ofS.thermophila YeeE-YeeD fusion proteins at 3.34- Å and 2.60-Å resolutions revealed their interactions. The association was evaluated by a binding assay using purifiedS.thermophila YeeE and YeeD. Based on these results, a model of the sophisticated uptake of thiosulfate ions by YeeE and YeeD is proposed.
Source: PLoS Biology: Archived Table of Contents - Category: Biology Authors: Source Type: research