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Journal Articles

In silico method to predict functional similarity between two RecA orthologs

Sghaier, H.*; Sato, Katsuya; Narumi, Issei

Journal of Biomolecular Screening, 16(4), p.457 - 459, 2011/04

https://doi.org/10.1177/1087057111400909
 Times Cited Count：1 Percentile：5.89(Biochemical Research Methods)

Journal Articles

Assessing the role of RecA protein in the radioresistant bacterium ${it Deinococcus geothermalis}$

Sghaier, H.*; Sato, Katsuya; Oba, Hirofumi*; Narumi, Issei

African Journal of Biochemistry Research, 4(4), p.111 - 118, 2010/04

http://academicjournals.org/journal/AJBR/article-abstract/4122D0C11282

Journal Articles

Identification of PprM; A Modulator of the PprI-dependent DNA damage response in ${it Deinococcus radiodurans}$

Oba, Hirofumi; Sato, Katsuya; Sghaier, H.; Yanagisawa, Tadashi*; Narumi, Issei

Extremophiles, 13(3), p.471 - 479, 2009/05

https://doi.org/10.1007/s00792-009-0232-8
 Times Cited Count：20 Percentile：40.36(Biochemistry & Molecular Biology)

${it Deinococcus radiodurans}$ possesses a DNA damage response mechanism that acts via the PprI protein to induce RecA and PprA proteins, both of which are necessary in conferring extreme radioresistance. In an effort to further delineate the nature of the DNA damage response mechanism in ${it D. radiodurans}$, we set out to identify novel components of the PprI-dependent signal transduction pathway in response to radiation stress. Here we demonstrate the discovery of a novel regulatory protein, PprM (a modulator of the PprI-dependent DNA damage response), which is a homolog of cold shock protein (Csp). Disruption of the ${it pprM}$ gene rendered ${it D. radiodurans}$ significantly sensitive to $$gamma$$-rays. PprM regulates the induction of PprA but not that of RecA. PprM belongs in a distinct clade of a subfamily together with Csp homologs from ${it D. geothermalis}$ and ${it Thermus thermophilus}$. Purified PprM is present as a homodimer under physiological conditions, as the case with ${it Escherichia coli}$ CspD. The ${it pprA pprM}$ double-disruptant strain exhibited higher sensitivity than the ${it pprA}$ or ${it pprM}$ single disruptant strains, suggesting that PprM regulates other hitherto unknown protein(s) important for radioresistance besides PprA. This study strongly suggests that PprM is involved in the radiation response mediated by PprI in ${it D. radiodurans}$.

Journal Articles

Discovery of a novel key protein in the radiation response mechanism of ${it Deinococcus radiodurans}$

Oba, Hirofumi; Sato, Katsuya; Kikuchi, Masahiro; Sghaier, H.; Yanagisawa, Tadashi*; Narumi, Issei

JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 57, 2008/11

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2008-055.pdf

no abstracts in English

Journal Articles

Role of LexA2 in radiation response mechanism of ${it Deinococcus radiodurans}$

Sato, Katsuya; Oba, Hirofumi; Sghaier, H.; Narumi, Issei

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 92, 2008/03

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2007-060.pdf

no abstracts in English

Journal Articles

Problems with the current deinococcal hypothesis; An Alternative theory

Sghaier, H.; Narumi, Issei; Sato, Katsuya; Oba, Hirofumi; Mitomo, Hiroshi*

Theory in Biosciences, 126(1), p.43 - 45, 2007/03

https://doi.org/10.1007/s12064-007-0004-x
 Times Cited Count：15 Percentile：85.71(Biology)

no abstracts in English

Journal Articles

${it Deinococcus radiodurans}$ DNA repair-promoting protein; Applications to biotech industry

Narumi, Issei; Oba, Hirofumi; Sghaier, H.; Sato, Katsuya

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 69, 2007/02

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2006-042.pdf

no abstracts in English

Journal Articles

Down-regulation of radioresistance by LexA2 in ${it Deinococcus radiodurans}$

Sato, Katsuya; Oba, Hirofumi; Sghaier, H.; Narumi, Issei

Microbiology, 152(11), p.3217 - 3226, 2006/11

In an effort to gain an insight into the role of LexA2 in the radiation response mechanism, ${it lexA2}$ disruptant strain was generated and investigated. The ${it lexA2}$ disruptant strains exhibited a much higher resistance to $$gamma$$ rays than the wild-type strain. Furthermore, a luciferase assay showed that ${it pprA}$ promoter activation was enhanced in the ${it lexA2}$ disruptant strain following $$gamma$$ irradiation. The increase in radioresistance of the ${it lexA2}$ disruptant strain is explained in part by the enhancement of ${it pprA}$ promoter activation.

Journal Articles

Characterization of a monofunctional catalase KatA from radioresistant bacterium ${it Deinococcus radiodurans}$

Kobayashi, Issei*; Tamura, Takashi*; Sghaier, H.; Narumi, Issei; Yamaguchi, Shotaro*; Umeda, Koichi*; Inagaki, Kenji*

Journal of Bioscience and Bioengineering, 101(4), p.315 - 321, 2006/04

https://doi.org/10.1263/jbb.101.315
 Times Cited Count：36 Percentile：65.35(Biotechnology & Applied Microbiology)

Catalase plays a key role in protecting cells against toxic reactive oxygen species. Here we report on the cloning, purification and characterization of a catalase (KatA) from the extremely radioresistant bacterium ${it Deinococcus radiodurans}$. The size of purified ${it D. radiodurans}$ KatA monomer was 65 kDa while gel filtration revealed that the size of the enzyme was 240 kDa, suggesting that KatA formed a homotetramer in solution. Purified KatA displayed a final specific activity of 68,800 U/mg of protein. The catalase activity of KatA was inhibited by sodium azide, sodium cyanide and 3-amino-1, 2, 4-triazole. The absorption spectrum of KatA exhibited a Soret band at 408 nm. The position of the spectral peak remained unchanged following reduction of KatA with dithionite. No peroxidase activity was found for KatA. These results demonstrate that ${it D. radiodurans}$ KatA is a typical monofunctional heme-containing catalase. The stability of KatA with respect to H$$_{2}$$O$$_{2}$$ stress was superior to that of commercially available ${it Aspergillus niger}$ and bovine liver catalases. The relative abundance of KatA in cells in addition to the H$$_{2}$$O$$_{2}$$ resistance property may play a role in the survival strategy of ${it D. radiodurans}$ against oxidative damage.

Journal Articles

Genomic confession of ${it Deinococcus radiodurans}$; It started out as a radiation resistant organism

Sghaier, H.; Mitomo, Hiroshi*; Narumi, Issei

Viva Origino, 33(4), p.243 - 257, 2005/12

Previously, analyses of ionizing-radiation-sensitive mutants of ${it Deinococcus radiodurans}$ and investigation into the genomic expression profile of the wild-type organism indicated a positive correlation between radiation resistance and desiccation tolerance phenotypes. Mainly because a terrestrial selective force for acquiring resistance to ionizing radiation was unfound, it has been assumed that the radiation resistance of ${it D. radiodurans}$ is an incidental phenotype due to its anhydrobiosis defense abilities. Here, following the stratification of the ${it D. radiodurans}$ genome, we discuss these issues from evolutionary, genomic, and experimental perspectives. Through the data collected we propose a reconciliatory model wherein radiation resistance is a unique molecular reflection of the early Earth resilience and desiccation tolerance is a mark of cells that colonized land during the Archaean epoch.

Oral presentation

Analysis of functionally deficient mutant of the DNA repair promoting protein from the radioresistant bacterium

Narumi, Issei; Oba, Hirofumi*; Sghaier, H.*; Van Long, N.*; Sato, Katsuya*

no journal, , 

no abstracts in English

Oral presentation

Why ${it Deinococci}$ retain their small plasmids?; Sequencing, annotation, and analysis

Sghaier, H.*; Oba, Hirofumi*; Sato, Katsuya*; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

DNA damage in radiation-resistant prokaryotes from evolutionary perspectives

Sghaier, H.; Oba, Hirofumi; Sato, Katsuya; Mitomo, Hiroshi*; Narumi, Issei

no journal, , 

The order in which DNA of radiation-resistant prokaryotes has been subjected to constant damage through radiation, elevated temperature, dry, or reactive oxygen species during Earth evolution is important to investigate for a better understanding of environment-genome evolutionary relationship. In analyzing model genomes of radioresistant prokaryotes (${it Deinococcus radiodurans}$ and ${it Pyrococcus furiosus}$), this study assesses the evolutionary itinerary of rough-and-tumble route on which their DNA was assaulted. Together with the examined literature, our analyses suggest the following elements. (1) Based on statistics of ORFs (Open Reading Frames) similarity relationships, we support the hypothesis that radiation resistance is a unique molecular reflection of the early Earth resilience and desiccation tolerance is a mark of cells that colonized land during the Archaean epoch. (2) Using unconventional methods, including oligonucleotide frequencies, numerous compelling data evoke the hypothesis that ${it Deinococcus radiodurans}$ and ${it Pyrococcus furiosus}$ progenitor(s) adapted, at least once, to the same environmental pressure, most probably ionizing radiation, through the acquisition of foreign genetic elements from one abnegator or compositionally similar abnegators. In conclusion, we present a model that satisfactorily accounts, from evolutionary perspectives, for DNA damage in radiation-resistant prokaryotes.

Oral presentation

Radiation response mechanism of the radioresistant bacterium ${it Deinococcus radiodurans}$; A Novel key protein "PprM"

Oba, Hirofumi; Sghaier, H.; Sato, Katsuya; Yanagisawa, Tadashi*; Narumi, Issei

no journal, , 

PprI, which is unique to ${it D. radiodurans}$, is invoked by present data as the most important protein for radiation response mechanism. However, despite the interest in mechanism underlying the radiation response in ${it D. raidodurans}$, little is known about the exact function of PprI protein. In this study, functional analysis of PprI protein was performed. Western blot analysis and gel shift assay suggested that PprI itself does not control directly the expression of ${it pprA}$ and ${it recA}$. We identified a novel regulatory protein PprM by 2D-PAGE. ${it pprM}$-disruptant strain showed significant sensitivity to $$gamma$$-rays. Western blot analysis revealed that PprM involves in RecA and PprA induction. By reporter assay it was found that PprM protein regulates the ${it pprA}$ expression at the promoter level. These results suggest that PprM is involved in the unique radiation response mechanism controlled by PprI in ${it D. radiodurans}$.

Oral presentation

${it Deinococcus radiodurans}$ DNA repair-promoting protein; Applications to biotech industry

Narumi, Issei; Oba, Hirofumi; Sghaier, H.; Sato, Katsuya

no journal, , 

no abstracts in English

Oral presentation

A Novel key protein "PprM" in the radiation response mechanism of ${it Deinococcus radiodurans}$

Oba, Hirofumi; Sghaier, H.; Sato, Katsuya; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

RecA of ${it Deinococcus geothermalis}$ provides insights into ancestral recombinational DNA repair

Sghaier, H.; Oba, Hirofumi; Sato, Katsuya; Mitomo, Hiroshi*; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

A Novel key protein "PprM" in the radiation response mechanism of the radioresistant bacterium ${it Deinococcus radiodurans}$

Oba, Hirofumi; Sato, Katsuya; Sghaier, H.; Narumi, Issei

no journal, , 

no abstracts in English

Oral presentation

Application of a novel DNA repair promoting protein toward bioindustry

Narumi, Issei; Oba, Hirofumi; Sato, Katsuya; Sghaier, H.

no journal, , 

no abstracts in English

Oral presentation

Role of the radiation respontive protein LexA2 in the radioresistant bacterium ${it Deinococcus radiodurans}$

Sato, Katsuya; Oba, Hirofumi; Sghaier, H.; Narumi, Issei

no journal, , 

no abstracts in English

23 (Records 1-20 displayed on this page)