Wang Y, Taylor J S, Gross M L
Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA.
J Am Soc Mass Spectrom. 1999 Apr;10(4):329-38. doi: 10.1016/S1044-0305(98)00158-5.
UV irradiation of oligodeoxynucleotides at 254 nm generates several different types of DNA photoproducts, including cis-syn cyclobutane pyrimidine dimers, pyrimidine[6-4] pyrimidone photoproducts and their Dewar valence isomers, and thymine-adenine photoproducts (TA*). Studies of photoproducts in oligodeoxynucleotides require the development of suitable structure determination methods such as mass spectrometry. In an earlier study (Vollmer et al. Int. J. Mass Spectrom. Ion Processes 1997, 165/166, 487-496), we showed that fast atom bombardment and tandem sector mass spectrometry can be used to locate the site of photomodification and identify most of the photoproducts of d(TATTAT). One goal of the present research was to expand the method to the more sensitive electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) methods. A second goal was to test the generality of the methods by investigating not only the photoproducts of d(TATTAT) but also those of three other oligodeoxynucleotides, d(GTATTAT), d(GGCTATAA), and d(AATTAA). The photoproducts of these sequences were separated by HPLC and gave characteristic fragment ions in postsource decompositions of MALDI-produced ions and collisionally activated decompositions of ESI-produced ions.
在254nm波长下对寡脱氧核苷酸进行紫外线照射会产生几种不同类型的DNA光产物，包括顺式-顺环丁烷嘧啶二聚体、嘧啶[6-4]嘧啶酮光产物及其杜瓦价异构体，以及胸腺嘧啶-腺嘌呤光产物（TA*）。对寡脱氧核苷酸中光产物的研究需要开发合适的结构测定方法，如质谱法。在早期的一项研究中（Vollmer等人，《国际质谱与离子过程杂志》，1997年，第165/166卷，第487 - 496页），我们表明快原子轰击和串联扇形质谱法可用于确定光修饰位点并鉴定d(TATTAT)的大多数光产物。本研究的一个目标是将该方法扩展到更灵敏的电喷雾电离（ESI）和基质辅助激光解吸/电离（MALDI）方法。第二个目标是通过不仅研究d(TATTAT)的光产物，还研究其他三种寡脱氧核苷酸d(GTATTAT)、d(GGCTATAA)和d(AATTAA)的光产物来测试这些方法的通用性。这些序列的光产物通过高效液相色谱法分离，并在MALDI产生的离子的源后分解和ESI产生的离子的碰撞激活分解中给出特征性碎片离子。
