Cheng Yiyu, Zeng Wenjuan, Cheng Yang, Zhang Jishuai, Zou Tao, Wu Kui, Wang Fuyi
School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan, 430081, PR China.
Beijing National Laboratory for Molecular Sciences; National Centre for Mass Spectrometry in Beijing; CAS Key Laboratory of Analytical Chemistry for Living Biosystems, CAS Research/Education Centre for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, PR China.
Rapid Commun Mass Spectrom. 2018 Dec 30;32(24):2152-2158. doi: 10.1002/rcm.8292.
Human telomeric DNA is reported to be a potential target for anticancer organometallic ruthenium(II) complexes, however, the interaction sites were not clearly discriminated and identified.
In the current study, tandem mass spectrometry (MS/MS) using collision-induced dissociation (CID) was firstly introduced to identify the interaction sites of an organometallic ruthenium(II) complex [(η -biphenyl)Ru(en)Cl][PF ] (1; en = ethylenediamine) with 5'-T T A G G G -3' (I), the repeating unit of human telomeric DNA, in both positive- and negative-ion mode at a low reaction molar ratio (1/I = 0.2) which was applied to preserve the site selectivity.
Mass spectrometric results showed that mono-ruthenated I was the main product under the conditions. In positive-ion mode, MS/MS results indicated that ruthenium complex 1 binds to T or G in strand I. However, in negative-ion mode, no efficient information was obtained for exact identification of ruthenation sites which may be attributed to losses of fragment ions due to charge neutralization by the coordination of the positively charged ruthenium complex to the short MS/MS fragments.
This is the first report of using top-down MS to characterize the interactions of organometallic ruthenium(II) complexes and human telomeric DNA. Thymine can be thermodynamically competitive with guanine for binding to ruthenium complexes even at low reaction molar ratio, which inspired us to explore in greater depth the significance of thymine binding.
据报道，人类端粒DNA是抗癌有机金属钌（II）配合物的潜在靶点，然而，相互作用位点尚未得到明确区分和鉴定。
在本研究中，首次引入了使用碰撞诱导解离（CID）的串联质谱（MS/MS），以在低反应摩尔比（1/I = 0.2）下的正离子和负离子模式下鉴定有机金属钌（II）配合物[(η -联苯)Ru(en)Cl][PF ]（1；en =乙二胺）与人类端粒DNA的重复单元5'-T T A G G G -3'（I）的相互作用位点，该低反应摩尔比用于保持位点选择性。
质谱结果表明，单钌化的I是该条件下的主要产物。在正离子模式下，MS/MS结果表明钌配合物1与链I中的T或G结合。然而，在负离子模式下，未获得用于准确鉴定钌化位点的有效信息，这可能归因于带正电荷的钌配合物与短MS/MS片段配位导致的电荷中和引起的碎片离子损失。
这是首次使用自上而下的质谱法表征有机金属钌（II）配合物与人类端粒DNA相互作用的报告。即使在低反应摩尔比下，胸腺嘧啶与鸟嘌呤在与钌配合物结合方面也具有热力学竞争性，这促使我们更深入地探索胸腺嘧啶结合的意义。
