Two distinct DNA ligase activities in mitotic extracts of the yeast Saccharomyces cerevisiae.
Two distinct DNA ligase activities in mitotic extracts of the yeast Saccharomyces cerevisiae.
复制标题
酿酒酵母有丝分裂提取物中两种不同的 DNA 连接酶活性。
DOI：
10.1093/nar/25.8.1485
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发表时间：
1997
影响因子：
14.9
通讯作者：
Tomkinson,AE
中科院分区：
文献类型：
--
作者：
Ramos,W;Tappe,N;Talamantez,J;Friedberg,EC;Tomkinson,AE
在哺乳动物细胞中已经鉴定出四种不同的生物化学DNA连接酶。其中DNA连接酶I在功能上与酿酒酵母CDC9基因编码的DNA连接酶同源。CDC9DNA连接酶被认为是该生物体中唯一的DNA连接酶。在本研究中，我们在酿酒酵母有丝分裂提取物中鉴定了第二种DNA连接酶活性，其层析性质不同于主要的DNA连接活性--CDC9 DNA连接酶。这种次要的DNA连接活性占细胞总DNA连接活性的5%-10%，形成90 kDa的酶-腺苷中间体，与Cdc9酶-腺苷中间体不同，它与寡聚(PDT)/聚(Ra)底物反应。微小DNA连接活性的水平不会因CDC9基因的突变或过度表达而改变。此外，90 kDa多肽不能被CDC9抗血清识别。由于这一次要物种似乎不是CDC9 DNA连接酶的修饰形式，它被命名为酿酒酵母DNA连接酶II。根据多核苷酸底物专一性的相似性，该酶可能是哺乳动物DNA连接酶III或IV的功能同源物。
Four biochemically distinct DNA ligases have been identified in mammalian cells. One of these enzymes, DNA ligase I, is functionally homologous to the DNA ligase encoded by theSaccharomyces cerevisiae CDC9gene. Cdc9 DNA ligase has been assumed to be the only species of DNA ligase in this organism. In the present study we have identified a second DNA ligase activity in mitotic extracts ofS.cerevisiaewith chromatographic properties different from Cdc9 DNA ligase, which is the major DNA joining activity. This minor DNA joining activity, which contributes 5–10% of the total cellular DNA joining activity, forms a 90 kDa enzyme-adenylate intermediate which, unlike the Cdc9 enzyme-adenylate intermediate, reacts with an oligo (pdT)/poly (rA) substrate. The levels of the minor DNA joining activity are not altered by mutation or by overexpression of theCDC9gene. Furthermore, the 90 kDa polypeptide is not recognized by a Cdc9 antiserum. Since this minor species does not appear to be a modified form of Cdc9 DNA ligase, it has been designated asS.cerevisiaeDNA ligase II. Based on the similarities in polynucleotide substrate specificity, this enzyme may be the functional homolog of mammalian DNA ligase III or IV.