Insights into strand displacement and processivity from the crystal structure of the protein-primed DNA polymerase of bacteriophage φ29
Insights into strand displacement and processivity from the crystal structure of the protein-primed DNA polymerase of bacteriophage φ29
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DOI：
10.1016/j.molcel.2004.10.019
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发表时间：
2004-11-19
期刊：
影响因子：
16
通讯作者：
Steitz, TA
中科院分区：
文献类型：
--
作者：
Kamtekar, S;Berman, AJ;Steitz, TA
来自噬菌体Phi 29的DNA聚合酶是B家族聚合酶，其使用蛋白质作为引物启动复制，将噬菌体基因组的第一个核苷酸连接到引发蛋白的特定丝氨酸的羟基。在2.2埃分辨率下测定的Phi29 DNA聚合酶的晶体结构为其非凡的持续合成能力和链置换活性提供了解释。同源建模表明，下游模板DNA在进入聚合酶活性位点之前通过隧道。这个隧道太小，不能容纳双链DNA，需要分离模板和非模板链。使用蛋白质引物的DNA聚合酶B家族的成员包含两个序列插入：一个形成以前在聚合酶中未观察到的结构域，而第二个类似于T7 RNA聚合酶的特异性环。Phi29 DNA聚合酶的高持续合成能力可以通过其对下游模板和上游双链体DNA的拓扑包围来解释。
The DNA polymerase from phage Phi29 is a B family polymerase that initiates replication using a protein as a primer, attaching the first nucleotide of the phage genome to the hydroxyl of a specific serine of the priming protein. The crystal structure of Phi29 DNA polymerase determined at 2.2 Angstrom resolution provides explanations for its extraordinary processivity and strand displacement activities. Homology modeling suggests that downstream template DNA passes through a tunnel prior to entering the polymerase active site. This tunnel is too small to accommodate double-stranded DNA and requires the separation of template and non-template strands. Members of the B family of DNA polymerases that use protein primers contain two sequence insertions: one forms a domain not previously observed in polymerases, while the second resembles the specificity loop of T7 RNA polymerase. The high processivity of Phi29 DNA polymerase may be explained by its topological encirclement of both the downstream template and the upstream duplex DNA.