title: Oxidative stress response of Deinococcus geothermalis via a cystine importer.
abstract: A cystine-dependent anti-oxidative stress response is characterized in Deinococcus geothermalis for the first time. Nevertheless, the same transcriptional directed Δdgeo_1985F mutant strain was revealed to have an identical phenotype to the wild-type strain, while the reverse transcriptional directed Δdgeo_1985R mutant strain was more resistant to oxidative stress at a certain concentration of H2O2than the wild-type strain. The wild-type and mutant strains expressed equal levels of superoxide dismutase and catalase under H2O2-induced stress. Although the expression levels of the general DNA-damage response-related genes recA, pprA, ddrA, and ddrB were up-regulated by more than five-fold in the wild-type strain relative to the Δdgeo_1985R mutant strain, the mutant strain had a higher survival rate than the wild-type under H2O2stress. The Δdgeo_1985R mutant strain highly expressed a cystine-transporter gene (dgeo_1986), at levels 150-fold higher than the wild-type strain, leading to the conclusion that this cystine transporter might be involved in the defensive response to H2O2stress. In this study, the cystine transporter was identified and characterized through membrane protein expression analysis, a cystine-binding assay, and assays of intracellular H2O2, cysteine, and thiol levels. The genedisrupted mutant strain of the cystine importer revealed high sensitivity to H2O2and less absorbed cystine, resulting in low concentrations of total thiol. Thus, the absorbed cystine via this cystine-specific importer may be converted into cysteine, which acts as a primitive defense substrate that non-enzymatically scavenges oxidative stress agents in D. geothermalis.
authors.affiliation: Department of Biology, Kyung Hee University, Seoul, 02447, Republic of Korea.
authors.forename: Minwook
authors.initials: M
authors.lastname: Kim
authors.affiliation: Division of Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea.
authors.forename: Sunwook
authors.initials: S
authors.lastname: Jeong
authors.affiliation: Division of Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea.
authors.forename: Sangyong
authors.initials: S
authors.lastname: Lim
authors.affiliation: Department of Visual Optics, Baekseok University, Cheonan, 31065, Republic of Korea.
authors.forename: Jeonggu
authors.initials: J
authors.lastname: Sim
authors.affiliation: Department of Biology, Kyung Hee University, Seoul, 02447, Republic of Korea.
authors.forename: Ho-Gun
authors.initials: HG
authors.lastname: Rhie
authors.affiliation: Department of Biology, Kyung Hee University, Seoul, 02447, Republic of Korea. sungjaelee@khu.ac.kr.|Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Republic of Korea. sungjaelee@khu.ac.kr.
authors.forename: Sung-Jae
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D003545:Cysteine / Q000378:metabolism*; D003553:Cystine / Q000378:metabolism*; D004249:DNA Damage; D034301:Deinococcus / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D005798:Genes, Bacterial; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000235:genetics; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D013438:Sulfhydryl Compounds; D003553:Cystine; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D003545:Cysteine
keywords: Deinococcus geothermalis; H2O2 scavenger; anti-oxidation; cystine importer; oxidative-stress response