Abstract
Rubrobacter radiotolerans is the most radio-resistant eubacterium without spore-formation in the life cycle, and its D37 is 16,000 Gy against gamma-rays. To understand the molecular mechanism of the high radio-resistance, we purified and characterized superoxide dismutase (SOD) of this organism as enzymatic radical scavenger, and then analyzed its genetic information. The purified SOD protein formed homo-tetramerization of 24,000 Da-monomer, while maintaining its enzymatic activity against potassium cyanide and hydrogen peroxide. We obtained a partial amino acid sequence of the protein and cloned the gene from it. Sequence analysis of the cloned gene indicated that the protein showed a similarity to other bacterial manganese SODs (Mn-SODs). Sequencing for adjacent regions of the gene showed that the gene had promoter elements with an open reading frame for putative PAS/PAC sensor protein at the 5'-adjacent region. Introduction of the gene into Escherichia coli cells lacking intrinsic SOD genes restored the cellular enzymatic activity and resistance to methyl viologen, indicating the gene at work. A mutant cell harboring this gene also became resistant against gamma-rays. The present results suggest that the protein in question is the Mn-SOD of R. radiotolerans, a good candidate as a radio-protection factor for this bacterial radio-resistance.
| Original language | English |
|---|---|
| Pages (from-to) | 735-742 |
| Number of pages | 8 |
| Journal | Journal of Radiation Research |
| Volume | 52 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Nov 1 2011 |
| Externally published | Yes |
Fingerprint
Keywords
- Radical scavenger
- Radio-resistance
- Rubrobacter radiotolerans
- Superoxide dismutase
ASJC Scopus subject areas
- Radiation
- Radiology Nuclear Medicine and imaging
- Health, Toxicology and Mutagenesis
Cite this
Characterization and radio-resistant function of manganese superoxide dismutase of rubrobacter radiotolerans. / Terato, Hiroaki; Suzuki, Katsuyuki; Nishioka, Nobuhiro; Okamoto, Atsushi; Shimazaki-Tokuyama, Yuka; Inoue, Yuko; Saito, Takeshi.
In: Journal of Radiation Research, Vol. 52, No. 6, 01.11.2011, p. 735-742.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization and radio-resistant function of manganese superoxide dismutase of rubrobacter radiotolerans
AU - Terato, Hiroaki
AU - Suzuki, Katsuyuki
AU - Nishioka, Nobuhiro
AU - Okamoto, Atsushi
AU - Shimazaki-Tokuyama, Yuka
AU - Inoue, Yuko
AU - Saito, Takeshi
PY - 2011/11/1
Y1 - 2011/11/1
N2 - Rubrobacter radiotolerans is the most radio-resistant eubacterium without spore-formation in the life cycle, and its D37 is 16,000 Gy against gamma-rays. To understand the molecular mechanism of the high radio-resistance, we purified and characterized superoxide dismutase (SOD) of this organism as enzymatic radical scavenger, and then analyzed its genetic information. The purified SOD protein formed homo-tetramerization of 24,000 Da-monomer, while maintaining its enzymatic activity against potassium cyanide and hydrogen peroxide. We obtained a partial amino acid sequence of the protein and cloned the gene from it. Sequence analysis of the cloned gene indicated that the protein showed a similarity to other bacterial manganese SODs (Mn-SODs). Sequencing for adjacent regions of the gene showed that the gene had promoter elements with an open reading frame for putative PAS/PAC sensor protein at the 5'-adjacent region. Introduction of the gene into Escherichia coli cells lacking intrinsic SOD genes restored the cellular enzymatic activity and resistance to methyl viologen, indicating the gene at work. A mutant cell harboring this gene also became resistant against gamma-rays. The present results suggest that the protein in question is the Mn-SOD of R. radiotolerans, a good candidate as a radio-protection factor for this bacterial radio-resistance.
AB - Rubrobacter radiotolerans is the most radio-resistant eubacterium without spore-formation in the life cycle, and its D37 is 16,000 Gy against gamma-rays. To understand the molecular mechanism of the high radio-resistance, we purified and characterized superoxide dismutase (SOD) of this organism as enzymatic radical scavenger, and then analyzed its genetic information. The purified SOD protein formed homo-tetramerization of 24,000 Da-monomer, while maintaining its enzymatic activity against potassium cyanide and hydrogen peroxide. We obtained a partial amino acid sequence of the protein and cloned the gene from it. Sequence analysis of the cloned gene indicated that the protein showed a similarity to other bacterial manganese SODs (Mn-SODs). Sequencing for adjacent regions of the gene showed that the gene had promoter elements with an open reading frame for putative PAS/PAC sensor protein at the 5'-adjacent region. Introduction of the gene into Escherichia coli cells lacking intrinsic SOD genes restored the cellular enzymatic activity and resistance to methyl viologen, indicating the gene at work. A mutant cell harboring this gene also became resistant against gamma-rays. The present results suggest that the protein in question is the Mn-SOD of R. radiotolerans, a good candidate as a radio-protection factor for this bacterial radio-resistance.
KW - Radical scavenger
KW - Radio-resistance
KW - Rubrobacter radiotolerans
KW - Superoxide dismutase
UR - http://www.scopus.com/inward/record.url?scp=82055180495&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=82055180495&partnerID=8YFLogxK
U2 - 10.1269/jrr.11105
DO - 10.1269/jrr.11105
M3 - Article
VL - 52
SP - 735
EP - 742
JO - Journal of Radiation Research
JF - Journal of Radiation Research
SN - 0449-3060
IS - 6
ER -