Structure of the gene 2.5 protein, a single-stranded DNA binding protein encoded by bacteriophage T7
Structure of the gene 2.5 protein, a single-stranded DNA binding protein encoded by bacteriophage T7
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DOI：
10.1073/pnas.171317698
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发表时间：
2001-08-14
影响因子：
11.1
通讯作者：
Ellenberger, T
中科院分区：
文献类型：
--
作者：
Hollis, T;Stattel, JM;Ellenberger, T
噬菌体T7的基因2.5蛋白（gp2.5）是单链DNA（ssDNA）结合蛋白，在DNA复制和重组中具有重要作用。除了结合DNA，gp2.5在复制过程中与T7 DNA聚合酶和T7引物解旋酶物理相互作用，以协调复制叉处的事件。我们已经确定了一个1.9埃的晶体结构的gp2.5，并表明，它有一个保守的OB-fold（寡糖/微管结合折叠），这是非常适合与ssDNA的相互作用。gp2.5和其他ssDNA结合蛋白的OB-折叠的叠加揭示了在其他晶体结构中与ssDNA的碱基堆叠的芳香残基的保守补丁，这表明gp2.5以类似的方式与ssDNA结合。二聚体形成和与T7 DNA聚合酶和引物解旋酶相互作用所需的gp2.5蛋白的酸性C-末端延伸似乎是灵活的，并且可以作为调节gp2.5的DNA结合亲和力的开关。
The gene 2.5 protein (gp2.5) of bacteriophage T7 is a single-stranded DNA (ssDNA) binding protein that has essential roles in DNA replication and recombination. In addition to binding DNA, gp2.5 physically interacts with T7 DNA polymerase and T7 primase-helicase during replication to coordinate events at the replication fork. We have determined a 1.9-Angstrom crystal structure of gp2.5 and show that it has a conserved OB-fold (oligosaccharide/oligonucleoticle binding fold) that is well adapted for interactions with ssDNA. Superposition of the OB-folds of gp2.5 and other ssDNA binding proteins reveals a conserved patch of aromatic residues that stack against the bases of ssDNA in the other crystal structures, suggesting that gp2.5 binds to ssDNA in a similar manner. An acidic C-terminal extension of the gp2.5 protein, which is required for dimer formation and for interactions with the T7 DNA polymerase and the primase-helicase, appears to be flexible and may act as a switch that modulates the DNA binding affinity of gp2.5.