OBJECTIVE: Bloom's syndrome is an autosomal recessive disorder characterized by genomic instability and a predisposition to many cancers. Mutations of the BLM gene (encoding a BLM helicase) may form a structure of the etiology of this disease. As a global pollutant, mercury poses a major threat to human health. The current study was conducted to elucidate the effects of Hg(2+) on the structure and activity of BLM642-1290 recombinant helicase, and to further explore the molecular mechanisms of mercury toxicity to the DNA helicase. METHODS: The effects of Hg(2+) on biological activity and structure of BLM642-1290 recombinant helicase were determined by fluorescence polarized, ultraviolet spectroscopic, and free-phosphorus assay technologies, respectively. RESULTS: The helicase activity, the DNA-binding activity, and the ATPase activity of BLM642-1290 recombinant helicase were inhibited by Hg(2+) treatment. The LMCT (ligand-to-metal charge transition) peaks of the helicase were enhanced with the increase of the Hg(2+) level. The LMCT peaks of the same concentration of helicase gradually increased over time. CONCLUSION: The biological activity of BLM642-1290 recombinant helicase is inhibited by Hg(2+) treatment. The conformation of the helicase is significantly altered by Hg(2+). There exist two binding sites between Hg(2+) and the helicase, which are located in the amino acid residues 1063-1066 and 940-944 of the helicase, respectively.
OBJECTIVE:Bloom's syndrome is an autosomal recessive disorder characterized by genomic instability and a predisposition to many cancers. Mutations of the BLM gene (encoding a BLMhelicase) may form a structure of the etiology of this disease. As a global pollutant, mercury poses a major threat to human health. The current study was conducted to elucidate the effects of Hg(2+) on the structure and activity of BLM642-1290 recombinant helicase, and to further explore the molecular mechanisms of mercury toxicity to the DNA helicase. METHODS: The effects of Hg(2+) on biological activity and structure of BLM642-1290 recombinant helicase were determined by fluorescence polarized, ultraviolet spectroscopic, and free-phosphorus assay technologies, respectively. RESULTS: The helicase activity, the DNA-binding activity, and the ATPase activity of BLM642-1290 recombinant helicase were inhibited by Hg(2+) treatment. The LMCT (ligand-to-metal charge transition) peaks of the helicase were enhanced with the increase of the Hg(2+) level. The LMCT peaks of the same concentration of helicase gradually increased over time. CONCLUSION: The biological activity of BLM642-1290 recombinant helicase is inhibited by Hg(2+) treatment. The conformation of the helicase is significantly altered by Hg(2+). There exist two binding sites between Hg(2+) and the helicase, which are located in the amino acid residues 1063-1066 and 940-944 of the helicase, respectively.
Authors: Olga P Ajsuvakova; Alexey A Tinkov; Michael Aschner; João B T Rocha; Bernhard Michalke; Margarita G Skalnaya; Anatoly V Skalny; Monica Butnariu; Maryam Dadar; Ioan Sarac; Jan Aaseth; Geir Bjørklund Journal: Coord Chem Rev Date: 2020-05-07 Impact factor: 22.315