HYDROXYL RADICAL INDUCED CROSS-LINKING OF CYTOSINE AND TYROSINE IN NUCLEOHISTONE
HYDROXYL RADICAL INDUCED CROSS-LINKING OF CYTOSINE AND TYROSINE IN NUCLEOHISTONE
复制标题
DOI：
10.1021/bi00456a020
复制
发表时间：
1990-01-30
期刊：
影响因子：
2.9
通讯作者：
DIZDAROGLU, M
中科院分区：
文献类型：
--
作者：
GAJEWSKI, E;DIZDAROGLU, M
羟基自由基诱导核组蛋白在缓冲水溶液中形成涉及胞嘧啶和酪氨酸的dna -蛋白交联。本研究采用气相色谱-质谱联用技术。可以利用。为了获得可能的胞嘧啶-酪氨酸交联的气相色谱-质谱性质，首先对胞嘧啶和酪氨酸的辐照水溶液进行了研究。观察到一个交联，其结构被确定为胞嘧啶碳6和酪氨酸碳3之间形成共价键的产物。采用选择离子监测的气相色谱-质谱法，在小牛胸腺核组蛋白的酸性水解物中鉴定出这种胞嘧啶-酪氨酸交联。-在n2o饱和水溶液中辐照。发现核组蛋白中dna -蛋白交联的产率与辐射剂量在100-500 Gy范围内呈线性关系。产率为0.05 nmol。核组蛋白中胞嘧啶-酪氨酸交联的形成机制涉及胞嘧啶和酪氨酸部分羟基加合自由基的自由基-自由基和/或自由基加成反应，在胞嘧啶的碳6和酪氨酸的碳3之间形成共价键。当氧存在于辐照溶液中时，没有观察到胞嘧啶-酪氨酸交联。
Hydroxyl radical induced formation of a DNA-protein cross-link involving cytosine and tyrosine in nucleohistone in buffered aqueous solution is reported. The technique of gas chromatography-mass spectrometry was used for this investigation. A .gamma.-irradiated aqueous mixture of cytosine and tryosine was first investigated in order to obtain gas chromatographic-mass spectrometric properties of possible cytosine-tyrosine cross-links. One cross-link was observed, and its structure was identified as the product from the formation of a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. With the use of gas chromatography-mass spectrometry with selected-ion monitoring, this cytosine-tyrosine cross-link was identified in acidic hydrolysates of calf thymus nucleohistone .gamma.-irradiated in N2O-saturated aqueous solution. The yield of this DNA-protein cross-link in nucleohistone was found to be a linear function of the radiation dose in the range of 100-500 Gy (J.cntdot.kg-1). This yield amounted to 0.05 nmol.cntdot.J-1. Mechanisms underlying the formation of the cytosine-tyrosine cross-link in nucleohistone were proposed to involve radical-radical and/or radical addition reactions of hydroxyl adduct radicals of cytosine and tyrosine moieties, forming a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. When oxygen was present in irradiated solutions, no cytosine-tyrosine cross-links were observed.