Palm mutants in DNA polymerases α and η alter DNA replication fidelity and translesion activity
Palm mutants in DNA polymerases α and η alter DNA replication fidelity and translesion activity
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DOI：
10.1128/mcb.24.7.2734-2746.2004
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发表时间：
2004-04-01
影响因子：
5.3
通讯作者：
Suzuki, M
中科院分区：
文献类型：
--
作者：
Niimi, A;Limsirichaikul, S;Suzuki, M
我们在酿酒酵母DNA聚合酶α中分离出与错误辨别缺陷相关的活性突变体。其中，L868F DNA聚合酶a的自发错误频率为100个核苷酸中3个，复制保真度比野生型（WT）聚合酶α低570倍。在体内，突变的DNA聚合酶赋予突变表型，并与msh2或msh6协同作用，这表明DNA聚合酶依赖的复制错误可以通过错配修复被识别和修复。在体外，L868F DNA聚合酶α催化顺式同步环丁烷嘧啶二聚体的高效绕过，将3' T延伸的效率是WT的26000倍。Phe34相当于翻译DNA聚合酶eta中的残基Leu868，而酵母DNA聚合酶eta的F34L突变体在体外降低了翻译DNA合成活性。这些数据表明，DNA聚合酶α的高保真DNA合成是酵母基因组稳定所必需的。这些数据还表明，翻译和复制DNA聚合酶中的苯丙氨酸和亮氨酸残基可能在这些酶类的功能进化中发挥了作用。
We isolated active mutants in Saccharomyces cerevisiae DNA polymerase alpha that were associated with a defect in error discrimination. Among them, L868F DNA polymerase a has a spontaneous error frequency of 3 in 100 nucleotides and 570-fold lower replication fidelity than wild-type (WT) polymerase alpha. In vivo, mutant DNA polymerases confer a mutator phenotype and are synergistic with msh2 or msh6, suggesting that DNA polymerase alpha-dependent replication errors are recognized and repaired by mismatch repair. In vitro, L868F DNA polymerase alpha catalyzes efficient bypass of a cis-syn cyclobutane pyrimidine dimer, extending the 3' T 26,000-fold more efficiently than the WT. Phe34 is equivalent to residue Leu868 in translesion DNA polymerase eta, and the F34L mutant of S. cerevisiae DNA polymerase eta has reduced translesion DNA synthesis activity in vitro. These data suggest that high-fidelity DNA synthesis by DNA polymerase alpha is required for genomic stability in yeast. The data also suggest that the phenylalanine and leucine residues in translesion and replicative DNA polymerases, respectively, might have played a role in the functional evolution of these enzyme classes.