Accessory proteins for DNA polymerase alpha activity with single-strand DNA templates.
Accessory proteins for DNA polymerase alpha activity with single-strand DNA templates.
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使用单链 DNA 模板实现 DNA 聚合酶 α 活性的辅助蛋白。
DOI：
10.1073/pnas.78.8.4723
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发表时间：
1981
影响因子：
11.1
通讯作者：
Baril,E
中科院分区：
文献类型：
--
作者：
Lamothe,P;Baril,B;Chi,A;Lee,L;Baril,E
从同步化HeLa细胞的合并的核提取物和微粒体后上清液中部分纯化了三种形式的DNA聚合酶α [DNA核苷酸转移酶（DNA导向的），EC 2.7.7.7]。这些酶，根据它们从DEAE-Bio-Gel中洗脱的顺序命名为DNA聚合酶α 1、α 2和α 3，它们利用单链DNA模板的能力不同。DNA聚合酶α 2与活化的和单链DNA作为模板引物具有相等的催化活性。DNA聚合酶α 1对单链DNA模板仅具有部分催化活性，而DNA聚合酶α 3对该模板基本上无活性。DNA聚合酶α 2的疏水亲和层析和磷酸纤维素层析的连续步骤用含有延伸的单链区域的DNA模板引物解析了聚合酶α活性和其催化活性所需的两个蛋白质因子（C1和C2）。在没有这些因子的情况下，DNA聚合酶α活性可以用活化的而不是单链DNA模板测量。在C1和C2因子的存在下，DNA聚合酶α与单链DNA模板的活性恢复到DNA聚合酶α 2与该模板的催化活性的约75%。
Three forms of DNA polymerase alpha [DNA nucleotidyltransferase (DNA-directed), EC 2.7.7.7] were partially purified from the combined nuclear extract and postmicrosomal supernatant solution of synchronized HeLa cells. These enzymes, designated DNA polymerases alpha 1, alpha 2, and alpha 3, on the basis of their order of elution from DEAE-Bio-Gel, differ in their abilities to utilize single-strand DNA templates. DNA polymerase alpha 2 has equal catalytic activities with activated and single-strand DNAs as template-primers. DNA polymerase alpha 1 has only partial catalytic activity with single-strand DNA templates, and DNA polymerase alpha 3 is essentially inactive with this template. Successive steps of hydrophobic affinity chromatography and phosphocellulose chromatography of DNA polymerase alpha 2 resolved the polymerase alpha activity and two protein factors (C1 and C2) that are required for its catalytic activity with a DNA template-primer that contains extended single-strand regions. In the absence of the factors, DNA polymerase alpha activity is measurable with activated but not single-strand DNA templates. In the presence of the C1 and C2 factors DNA polymerase alpha activity with single-strand DNA templates is restored to about 75% of the catalytic activity of DNA polymerase alpha 2 with this template.