Electrospray Ionization Mass Spectrometry Characterization of Interactions of Newly Identified Water Disinfection Byproducts Halobenzoquinones with Oligodeoxynucleotides

• Published in: Environmental science & technology Vol. 44; no. 24; pp. 9557 - 9563
• Main Authors: Anichina, Janna, Zhao, Yuli, Hrudey, Steve E, Le, X. Chris, Li, Xing-Fang
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.12.2010
• Subjects: Benzoquinones - analysis; Benzoquinones - chemistry; Biological and medical sciences; By products; Disinfectants - analysis; Disinfectants - chemistry; Disinfection; Disinfection & disinfectants; Drug Interactions; Ecotoxicology and Human Environmental Health; Food toxicology; Ions; Isotopes; Mass spectrometry; Medical sciences; Molecules; Oligodeoxyribonucleotides - analysis; Oligodeoxyribonucleotides - chemistry; Polymerization; Scientific imaging; Spectrometry, Mass, Electrospray Ionization; Toxicity; Toxicology; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; Water Purification; Characterization; Drinking water treatment; Poison interaction; Ionization; Secondary pollutant; By product; Mass spectrometry; Electrospray; Public health
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es1024492

Four halobenzoquinones, 2,6-dibromo-1,4-benzoquinone, 2,6-dichloro-1,4-benzoquinone, 2,6-dichloro-3-methyl-1,4-benzoquinone, and 2,3,6-trichloro-1,4-benzoquinone, were recently identified as drinking water disinfection byproducts. Understanding their interactions with biomolecules could provide useful insights into their potential toxic effects. We report here electrospray ionization mass spectrometry characterization of the interactions between these new halobenzoquinone disinfection byproducts and oligodeoxynucleotides. The study demonstrates that 2,6-dibromo-1,4-benzoquinone exhibits much stronger binding to single- and double-stranded oligodeoxynucleotides than chlorobenzoquinones. The binding affinity of 2,6-dibromo-1,4-benzoquinone to oligodeoxynucleotides is similar to that of ethidium bromide, a well-known intercalator and carcinogen. Tandem mass spectrometry characterization confirms the formation of 1:1 and 2:1 complexes of 2,6-dibromo-1,4-benzoquinone binding to oligodeoxynucleotides. Collision-induced dissociation analysis of these adducts demonstrates neutral loss and charge separation, suggesting that 2,6-dibromo-1,4-benzoquinone binds to oligodeoxynucleotides through partial intercalation and H-bonding modes. The three chlorobezoquinones also form 1:1 adducts with the oligodeoxynucleotides, but their binding to the oligodeoxynucleotides was much weaker compared to that of 2,6-dibromo-1,4-benzoquinone. The relative binding affinity of the studied disinfection byproducts to oligodeoxynucleotides is in the order of 2,6-dibromo-1,4-benzoquinone≫2,6-dichloro-1,4-benzoquinone > 2,6-dichloro-3-methyl-1,4-benzoquinone ∼ 2,3,6-trichloro-1,4-benzoquinone, indicating potential structural effects on the interactions of halobenzoquinones with oligodeoxynucleotides.