title: The three catalases in Deinococcus radiodurans: Only two show catalase activity.
abstract: Deinococcus radiodurans, which is extremely resistant to ionizing radiation and oxidative stress, is known to have three catalases (DR1998, DRA0146, and DRA0259). In this study, to investigate the role of each catalase, we constructed catalase mutants (Δdr1998, ΔdrA0146, and ΔdrA0259) of D. radiodurans. Of the three mutants, Δdr1998 exhibited the greatest decrease in hydrogen peroxide (H2O2) resistance and the highest increase in intracellular reactive oxygen species (ROS) levels following H2O2 treatments, whereas ΔdrA0146 showed no change in its H2O2 resistance or ROS level. Catalase activity was not attenuated in ΔdrA0146, and none of the three bands detected in an in-gel catalase activity assay disappeared in ΔdrA0146. The purified His-tagged recombinant DRA0146 did not show catalase activity. In addition, the phylogenetic analysis of the deinococcal catalases revealed that the DR1998-type catalase is common in the genus Deinococcus, but the DRA0146-type catalase was found in only 4 of 23 Deinococcus species. Taken together, these results indicate that DR1998 plays a critical role in the anti-oxidative system of D. radiodurans by detoxifying H2O2, but DRA0146 does not have catalase activity and is not involved in the resistance to H2O2 stress.
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Republic of Korea; Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Sun-Wook
authors.initials: SW
authors.lastname: Jeong
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Republic of Korea.
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Jung
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Republic of Korea.
authors.forename: Min-Kyu
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Republic of Korea.
authors.forename: Ho Seong
authors.initials: HS
authors.lastname: Seo
authors.affiliation: Department of Biological Sciences, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764, Republic of Korea.
authors.forename: Heon-Man
authors.initials: HM
authors.lastname: Lim
authors.affiliation: Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Republic of Korea. Electronic address: saylim@kaeri.re.kr.
authors.forename: Sangyong
authors.initials: S
authors.lastname: Lim
mesh_terms: D002374:Catalase / Q000145:classification / Q000378:metabolism*; D034301:Deinococcus / Q000201:enzymology*; D004789:Enzyme Activation; D006861:Hydrogen Peroxide / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002374:Catalase
keywords: Catalase; DRA0146; Deinococcus radiodurans; Oxidative stress