Key Laboratory of Molecular Biophysics, the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China;
Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115.
Proc Natl Acad Sci U S A. 2017 Mar 21;114(12):E2310-E2318. doi: 10.1073/pnas.1700280114. Epub 2017 Mar 6.
A DNA polymerase is encoded by the deep-sea vent phage NrS-1. NrS-1 has a unique genome organization containing genes that are predicted to encode a helicase and a single-stranded DNA (ssDNA)-binding protein. The gene for an unknown protein shares weak homology with the bifunctional primase-polymerases (prim-pols) from archaeal plasmids but is missing the zinc-binding domain typically found in primases. We show that this gene product has efficient DNA polymerase activity and is processive in DNA synthesis in the presence of the NrS-1 helicase and ssDNA-binding protein. Remarkably, this NrS-1 DNA polymerase initiates DNA synthesis from a specific template DNA sequence in the absence of any primer. The de novo DNA polymerase activity resides in the N-terminal domain of the protein, whereas the C-terminal domain enhances DNA binding.
一种 DNA 聚合酶由深海喷口噬菌体 NrS-1 编码。NrS-1 具有独特的基因组组织，包含预测编码解旋酶和单链 DNA（ssDNA）结合蛋白的基因。一个未知蛋白的基因与来自古细菌质粒的双功能引物聚合酶（prim-pols）具有微弱的同源性，但缺少通常在引物酶中发现的锌结合域。我们表明，该基因产物具有有效的 DNA 聚合酶活性，并且在 NrS-1 解旋酶和 ssDNA 结合蛋白的存在下，在 DNA 合成中具有连续性。值得注意的是，这种 NrS-1 DNA 聚合酶在没有任何引物的情况下，从特定的模板 DNA 序列起始 DNA 合成。从头 DNA 聚合酶活性位于蛋白质的 N 端结构域，而 C 端结构域增强 DNA 结合。
