While MALDI-MS of intact genomic DNA is unheard of, actually many DNA adducts can be detected in this way under certain MALDI conditions: relatively high molar ratio of DNA nucleobases to matrix (0.01 to 0.3), hot matrix (CCA), and high laser fluence. This is because many DNA adducts create "bubbles" on dsDNA (disruption of base pairing), making it easier for these adducts as modified nucleobases to be jettisoned by the laser-derived energy of MALDI (jettison mass spectrometry or JeMS). The method also works for other nucleic acid species, namely nucleobases, nucleosides, nucleotides, and RNA. Examples of what we have detected in this way are as follows: methyladenine in E. coli DNA, 5-hydroxymethylcytosine in human brain DNA, melphalan-adenine in leukocyte DNA from patients on corresponding chemotherapy, wybutosine in tRNA, benzyl DNA adducts in E. coli cell culture treated with benzyl bromide, and various DNA adducts formed in test tube exposure experiments with calf thymus DNA. Noteworthy, in the chemotherapy study, principle component analysis of the data encourages the hypothesis that patient DNA undergoes much more damage than just melphalan adducts. Overall, our work leads to the preliminary generalization that about 5 fmol of a nucleobase deficient in base pairing, and present in a MALDI spot, will be detected by JeMS (on the equipment that we used), irrespective of the type of nucleic acid species which houses it, as long as the nucleobase is relatively basic such as A, C, or G.

中文翻译：

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核酸种类的 Jetison-MS。


虽然完整基因组 DNA 的 MALDI-MS 闻所未闻，但实际上在某些 MALDI 条件下可以通过这种方式检测许多 DNA 加合物：DNA 核碱基与基质的摩尔比相对较高（0.01 至 0.3）、热基质 (CCA) 和高摩尔比。激光能量密度。这是因为许多 DNA 加合物在 dsDNA 上产生“气泡”（碱基配对的破坏），使得这些加合物作为修饰的核碱基更容易被 MALDI（抛弃质谱法或 JeMS）的激光衍生能量抛弃。该方法也适用于其他核酸种类，即核碱基、核苷、核苷酸和 RNA。我们以这种方式检测到的例子如下：大肠杆菌DNA中的甲基腺嘌呤、人脑DNA中的5-羟甲基胞嘧啶、接受相应化疗的患者的白细胞DNA中的美法仑-腺嘌呤、tRNA中的威布托辛、大肠杆菌中的苄基DNA加合物。用苄基溴处理的大肠杆菌细胞培养物，以及在小牛胸腺 DNA 的试管暴露实验中形成的各种 DNA 加合物。值得注意的是，在化疗研究中，数据的主成分分析支持了这样的假设：患者 DNA 遭受的损伤比仅仅马法兰加合物要大得多。总体而言，我们的工作得出了初步概括，即无论核酸种类如何，JeMS（在我们使用的设备上）都将检测到 MALDI 点中存在碱基配对缺陷的约 5 fmol 核碱基只要核碱基是相对碱性的，例如 A、C 或 G，就可以容纳它。