Cytosine photoproduct-DNA glycosylase in Escherichia coli and cultured human cells.
Cytosine photoproduct-DNA glycosylase in Escherichia coli and cultured human cells.
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大肠杆菌和培养的人类细胞中的胞嘧啶光产物-DNA 糖基化酶。
DOI：
10.1021/bi00430a010
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发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
Duker,NJ
中科院分区：
文献类型：
--
作者：
Weiss,RB;Gallagher,PE;Brent,TP;Duker,NJ
1988年10月12日收到的修订稿摘要：紫外线照射DNA会产生多种嘧啶碱基损伤。比较了大肠杆菌核酸内切酶III和人淋巴母细胞核酸内切酶在修饰胞嘧啶基段切割DNA的活性。细菌和人类的酶都以游离碱的形式释放这种胞嘧啶光解产物。糖基酶活性与反应时间、酶的用量和底物的辐射剂量呈线性关系。这两种酶的活性都同样受到单价和二价阳离子的抑制。DNA测序分析表明，内核溶解切口处的基因座为胞嘧啶。这些化合物既不是环丁烷嘧啶二聚体，6-(L，2-二氢-2-氧代-4-嘧啶基)-5-甲基-2，4(L/f，3//)-嘧啶二酮，也不是脱嘧啶中心。这种胞嘧啶光产物可以通过高效液相色谱从未经修饰的胞嘧啶中分离出来。这种分离应该有助于鉴定这种修饰的胞嘧啶并阐明其生物学意义。大肠杆菌内切酶III已被证明负责修复DNA中的各种单体嘧啶损伤，包括由UV1辐射造成的损伤(Radman，1976；Gates&Linn，1977)以及由化学或物理因素引起的化学氧化(Gates&Linn，1977；Demple&Linn，1980,1982；Katcher&Wallace，1983；Bremer&Lindahl，1984)。在培养的人类细胞中发现了切割紫外线照射的DNA的内切酶活性(Brent，1972；Duker&Teebor，1975)。研究表明，这种被称为人紫外线核酸内切酶的活性是针对紫外线照射的DNA中的非嘧啶二聚体损伤的。Thishuman内切酶和大肠杆菌内切酶III一样，也识别Os04氧化或X辐射DNA中的碱基损伤(Brent，1973,1976,1983；Doetsch等人，1987)。这种活性被认为是人类对应于核酸内切酶III(Teebor等人，1978年)。胸腺嘧啶二醇被认为是所有这些处理产生的常见的核酸内切酶敏感损伤，因此是所有这些DNA底物的切割部位，既有内切酶III，也有人类活动(Teebor等人，1978年)。然而，最近已经证实，DNA胞嘧啶光产物是DNA紫外线照射后的核酸内切酶III的底物(Doetsch等人，1986；Helland等人，1986；Weiss&Duker，1986,1987)和小牛胸腺内切酶的底物(Doetsch等人，1986；Helland等人(1986))。
Revised Manuscript Received October 12, 1988 abstract: Ultraviolet irradiation of DNA produces a variety of pyrimidine base damages. The activities of Escherichia coli endonuclease III and a human lymphoblast endonuclease that incises ultraviolet-irradiated DNA at modified cytosine moieties were compared. Both the bacterial and human enzymes release this cytosine photoproduct as a free base. Theseglycosylase activities are linear with times of reaction, quantities of enzyme, and irradiation dosages of the substrates. Both enzyme activities are similarly inhibited by the addition of monovalent and divalent cations. Analysis by DNA sequencing identified loci of endonucleolytic incision as cytosines. These are neither cyclobutane pyrimidine dimers, 6-(l, 2-dihydro-2-oxo-4-pyrimidinyl)-5-methyl-2, 4 (l/f, 3//)-pyrimidinediones, nor apyrimidinic sites. This cytosine photoproduct is separable from unmodified cytosine by high-performance liquid chromatography. This separationshould facilitate identification of this modified cytosine and elucidation of its biological significance.Escherichia coli endonuclease III has been shown to be responsible for the repair of various monomeric pyrimidine damages in DNA, including both damages produced by UV1 irradiation (Radman, 1976; Gates & Linn, 1977) and chemical oxidation caused by chemical or physical agents (Gates & Linn, 1977; Demple & Linn, 1980, 1982; Katcher & Wallace, 1983; Breimer & Lindahl, 1984). An endonuclease activity that incises ultraviolet-irradiated DNA was found in cultured human cells (Brent, 1972; Duker & Teebor, 1975). It was demonstrated that this activity, termed the human UV en-donuclease, is directed against non-pyrimidine dimer lesions in UV-irradiatedDNA. Thishuman endonuclease, like E. coli endonuclease III, also recognizes base damages in Os04-oxidized or X-irradiated DNAs (Brent, 1973, 1976, 1983; Doetsch et al., 1987). This activity was suggested to be the human counterpart to endonuclease III (Teebor et al., 1978). Thymine glycol had been thought to be the common endonuclease-sensitive lesion produced by all of these treatments and therefore the site of incision of all these DNA substrates, both by endonuclease III and by the human activity (Teebor et al., 1978). However, it has recently been established that a DNA cytosine photoproduct is a substrate for both endonuclease III (Doetsch et al., 1986; Helland et al., 1986; Weiss & Duker, 1986, 1987) and a calf thymus endonuclease following UV irradiation of the DNA (Doetsch et al., 1986; Helland et al „1986).