title: Identification of a Novel Dye-Decolorizing Peroxidase, EfeB, Translocated by a Twin-Arginine Translocation System in Streptococcus thermophilus CGMCC 7.179.
abstract: Streptococcus thermophilus is a facultative anaerobic bacterium that has the ability to grow and survive in aerobic environments, but the mechanism for this remains unclear. In this study, the efeB gene, encoding a dye-decolorizing peroxidase, was identified in the genome of Streptococcus thermophilus CGMCC 7.179, and purified EfeB was able to decolorize reactive blue 5. Strikingly, genes encoding two components (TatA and TatC) of the twin-arginine translocation (TAT) system were also found in the same operon with the efeB gene. Knocking out efeB or tatC resulted in decreased growth of the strain under aerobic conditions, and complementation of the efeB-deficient strains with the efeB gene enhanced the biomass of the hosts only in the presence of the tatC gene. Moreover, it was proved for both S. thermophilus CGMCC 7.179 and Escherichia coli DE3 that EfeB could be translocated by the TAT system of S. thermophilus. In addition, the transcriptional levels of efeB and tatC increased when the strain was cultured under aerobic conditions. Overall, these results provide the first evidence that EfeB plays a role in protecting cells of S. thermophilus from oxidative stress, with the assistance of the TAT system.
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors.forename: Yongping
authors.initials: Y
authors.lastname: Xin
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors.forename: Shiyi
authors.initials: S
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China kongjian@sdu.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Kong
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D000880:Anthraquinones / Q000378:metabolism*; D018533:Biomass; D001711:Biotransformation; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D009876:Operon; D009195:Peroxidase / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D021381:Protein Transport; D048249:Streptococcus thermophilus / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism*; D000069294:Twin-Arginine-Translocation System / Q000235:genetics / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; C544286:Reactive Blue 5; D000069294:Twin-Arginine-Translocation System; D009195:Peroxidase