Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, AL: 0800 C, Ottawa, Ontario K1A 0K9, Canada.
Exposure and Biomonitoring Division, Environmental Health Science and Research Bureau, Environmental and Radiation Health Sciences Directorate, Healthy Environments and Consumer Safety Branch, Health Canada, 50 Colombine Driveway, AL: 0800 C, Ottawa, Ontario K1A 0K9, Canada.
Talanta. 2016 Oct 1;159:93-102. doi: 10.1016/j.talanta.2016.05.074. Epub 2016 May 30.
A method for nontargeted screening for covalent DNA adducts was developed using combination of neutral loss scan and product ion scan in a hybrid linear-ion-trap - triple quadrupole mass spectrometer system. DNA 2'-deoxynucleosides and adducts eluted from liquid chromatography were first analyzed in neutral loss mode to screen for the neutral loss of the deoxyribose moiety (M+H-116) from the protonated molecular ion (M+H). The product ion scan was subsequently used to elucidate the structures for the molecular ions observed from the peaks in the neutral loss scan chromatogram. The synthesized DNA adducts were used to evaluate the developed method by reaction of 20-mer DNA oligonucleotide with two direct agents respectively, specifically phenyl glycidyl ether and styrene-7,8-oxide. The modification selectivity of two compounds to the four nitrogenous bases on DNA sequence was also investigated in this study. The results showed that the two compounds had different modification selectivity to the four bases. Both compounds could modify all four nitrogenous bases (i.e. adenine, guanine, thymine, and cytosine) on DNA sequences to form various covalent DNA adducts. While phenyl glycidyl ether modified almost all of thymidine on DNA sequence, styrene-7,8-oxide, on the other hand, modified only a small portion of thymidine. The developed method proved possibly a potential tool for screening of unknown DNA adducts as exposure biomarkers of contaminants to human in the environment.
建立了一种使用中性丢失扫描和产物离子扫描相结合的方法，在混合线性离子阱-三重四极杆质谱系统中用于非靶向筛选共价 DNA 加合物。DNA 2'-脱氧核苷和从液相色谱中洗脱的加合物首先在中性丢失模式下进行分析，以筛选出从质子化分子离子(M+H)中脱氧核糖部分(M+H-116)的中性丢失。随后使用产物离子扫描来阐明在中性丢失扫描色谱图中观察到的分子离子的结构。通过将 20 聚体 DNA 寡核苷酸分别与两种直接试剂（苯缩水甘油醚和苯乙烯-7,8-氧化物）反应，用合成的 DNA 加合物来评估所开发的方法。本研究还研究了两种化合物对 DNA 序列上四个含氮碱基的修饰选择性。结果表明，两种化合物对四个碱基具有不同的修饰选择性。两种化合物都可以修饰 DNA 序列上的所有四个含氮碱基（即腺嘌呤、鸟嘌呤、胸腺嘧啶和胞嘧啶），形成各种共价 DNA 加合物。虽然苯缩水甘油醚几乎修饰了 DNA 序列上的所有胸腺嘧啶，但另一方面，苯乙烯-7,8-氧化物只修饰了一小部分胸腺嘧啶。所开发的方法可能成为一种潜在的工具，用于筛选环境中污染物对人类暴露的未知 DNA 加合物作为生物标志物。
