title: Differential regulation and activity against oxidative stress of Dps proteins in Bacillus cereus.
abstract: In this study, the sequence similarity, structure, ferroxidase activity and efficacy in antagonizing oxidative stress of three Dps-like proteins, Dps1, Dps2 and Dps3, encoded by Bacillus cereus were comparatively analyzed. The three Dps-like proteins are homologous to other bacterial Dps proteins that exhibit ferroxidase activity. Both Dps1 and Dps2 have a typical Dps spherical structure, but Dps3 has a unique filamentous structure. Several dps mutant strains were generated to investigate the functional role of dps genes in cell protection. The dps1 null strain was the most labile to oxidative stress in the stationary phase, and the loss of dps2 resulted in greater sensitivity to peroxide exposure compared with the other mutant strains in the log phase. Interestingly, after simultaneous deletion of dps1 and dps2, the survival rate was dramatically reduced by approximately 5 log in the stationary phase. Immunoblotting analysis demonstrated that Dps1 and Dps2 in the wild-type strain were induced by oxidative stress, and Dps3 responded to general stress in the log phase. Constitutively high expression of Dps2 in a perR null mutant and PerR-specific binding of the promoter region of dps2 confirmed Dps2 as a member of the PerR regulon. In addition, the expression of Dps1 and Dps2, absent any stress, was initiated in the log phase and was abundant in the stationary phase, suggesting that the expression of Dps1 and Dps2 was dependent on the bacterial growth stage. In summary, the three Dps proteins conferred cellular protection, particularly from oxidative stress, and were differentially regulated in response to varied stress conditions.
authors.forename: Jwu-Ching
authors.initials: JC
authors.lastname: Shu
authors.forename: Po-Chi
authors.initials: PC
authors.lastname: Soo
authors.forename: Jung-Chi
authors.initials: JC
authors.lastname: Chen
authors.forename: Shu-Han
authors.initials: SH
authors.lastname: Hsu
authors.forename: Lei-Chin
authors.initials: LC
authors.lastname: Chen
authors.forename: Chien-Yen
authors.initials: CY
authors.lastname: Chen
authors.forename: Shih-Hsiung
authors.initials: SH
authors.lastname: Liang
authors.forename: Leh-Miauh
authors.initials: LM
authors.lastname: Buu
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D001409:Bacillus cereus / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D002570:Ceruloplasmin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D050296:Microbial Viability / Q000187:drug effects; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010545:Peroxides / Q000633:toxicity; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D010545:Peroxides; D002570:Ceruloplasmin