CATION LABELING MASS SPECTROMETRY OF DNA ADDUCTS

我们提出了基于化学标记和质谱（MS）的新方法，用于发现和定性分析人类样本中未知的DNA加合物。新的、笨重的、非极性的阳离子试剂将被合成和测试，作为DNA加合物的核苷酸和核苷版本的标记试剂。化学标记的主要目的是使所有DNA加合物对质谱分析具有高度和相等（或接近）的灵敏度，特别是激光解吸（包括MALDI）和电喷雾形式的质谱将被使用。在前一种情况下，将强调傅立叶变换质谱仪（FTMS）上的大光斑激光解吸。该项目的部分原因是我们未发表的观察结果，即我们制备的大体积非极性化合物对MALDI-MS非常敏感。用这种类型的试剂标记的DNA加合物也可能以高灵敏度被检测到。如果可以在R21中证明这一点，那么随后的R33将涉及进一步优化该技术，最终在项目中应用于从大型尸检人体组织样本中提取的DNA，从而使整个方法完全成熟。

We propose new methodology based on chemical labeling and mass spectrometry (MS) for the discovery and qualitative analysis of unknown DNA adducts in human samples. Novel, bulky, nonpolar cationic reagents will be synthesized and tested as labeling reagents for both nucleotide and nucleoside versions of DNA adducts. The primary purpose of the chemical labeling is to make all DNA adducts highly and equally (or near so) sensitive for analysis by MS. Especially laser desorption (including MALDI) but also electrospray forms of MS will be used. In the former case, large spot laser desorption on a Fourier transform mass spectrometer (FTMS) will be emphasized. The project is stimulated in part by our unpublished observation that bulky, nonpolar compounds that we have prepared are very sensitive by MALDI-MS. Potentially a DNA adduct labeled with a reagent of this type also can be detected with high sensitivity. If this can be demonstrated in an R21, then the ensuing R33 would involve further optimization of the technique, with eventual application in the project to DNA extracted from large, autopsy, human tissue samples to bring the overall methodology to full maturity.