title: ydjN encodes an S-sulfocysteine transporter required by Escherichia coli for growth on S-sulfocysteine as a sulfur source.
abstract: Sulfur is an essential element for growth and many physiological functions. As sulfur sources for Escherichia coli and related bacteria, specific transporters import various sulfur-containing compounds from the environment. In this study, we identified and characterized an alternative function of the cystine transporter YdjN in E. coli as a transporter of S-sulfocysteine, a sulfur-containing intermediate in the assimilatory cysteine biosynthesis that is used as a sulfur source for the growth of E. coli We also demonstrated that the transport of S-sulfocysteine via YdjN depends on the transcriptional regulator CysB, a master regulator that controls most of the genes involved in sulfur assimilation and cysteine metabolism. We found that the use of S-sulfocysteine as a sulfur source depends on glutathione because mutations in glutathione biosynthetic genes abolish growth when S-sulfocysteine is used as a sole sulfur source, thereby supporting the previous findings that the conversion of S-sulfocysteine to cysteine is catalyzed by glutaredoxins. To the best of our knowledge, this is the first report of a functional S-sulfocysteine transporter across organisms, which strongly supports the hypothesis that S-sulfocysteine is not only a metabolic intermediate but also a physiologically significant substance in specific natural environments.
authors.affiliation: Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Takei
authors.affiliation: Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan gen_nonaka@ajinomoto.com.
authors.forename: Gen
authors.initials: G
authors.lastname: Nonaka
mesh_terms: D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D003545:Cysteine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005978:Glutathione / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D001426:Bacterial Proteins; C062886:CysB protein, Bacteria; D026901:Membrane Transport Proteins; C000604954:YdjN protein, E coli; D013455:Sulfur; C011119:S-sulphocysteine; D005978:Glutathione; D003545:Cysteine
keywords: S-sulfocysteine; cysB; cysteine metabolism; sulfur transport; ydjN