RRC ID 35405
Author Terato H, Suzuki K, Nishioka N, Okamoto A, Shimazaki-Tokuyama Y, Inoue Y, Saito T.
Title Characterization and radio-resistant function of manganese superoxide dismutase of Rubrobacter radiotolerans.
Journal J. Radiat. Res.
Abstract Rubrobacter radiotolerans is the most radio-resistant eubacterium without spore-formation in the life cycle, and its D(37) 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.
Volume 52(6)
Pages 735-42
Published 2011
PII JST.JSTAGE/jrr/11105
PMID 21971036
MeSH Actinobacteria / enzymology* Actinobacteria / genetics Actinobacteria / radiation effects* Amino Acid Sequence Bacterial Proteins / chemistry Bacterial Proteins / genetics Bacterial Proteins / metabolism Base Sequence DNA, Bacterial / genetics Gamma Rays Genes, Bacterial Molecular Sequence Data Protein Structure, Quaternary Radiation Tolerance / genetics Radiation Tolerance / physiology Superoxide Dismutase / chemistry Superoxide Dismutase / genetics Superoxide Dismutase / metabolism*
IF 2.031
Times Cited 6
Prokaryotes E. coli pACYC184