Dda helicase unwinds a DNA-PNA chimeric substrate: evidence for an inchworm mechanism.
Dda helicase unwinds a DNA-PNA chimeric substrate: evidence for an inchworm mechanism.
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Dda 解旋酶解开 DNA-PNA 嵌合底物：尺蠖机制的证据。
DOI：
10.1016/j.bmcl.2006.01.013
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Raney,KevinD
中科院分区：
文献类型：
--
作者：
Spurling,TravisL;Eoff,RobertL;Raney,KevinD
解旋酶是普遍存在的酶，参与DNA代谢的所有方面，包括复制、修复、重组和转录。通过制备DNA-PNA嵌合底物，研究了噬菌体T4 Dda解旋酶的作用机制。令人惊讶的是，Dda能够解旋在酶的加载链中含有12个PNA部分的底物。我们提出了一种机制，Dda解旋酶包含两个不同的DNA结合域，允许尺蠖易位机制。酶的单个步骤足以解开DNA-PNA嵌合体，因为几个碱基对由于热磨损而自发地熔化。因此，Dda解旋酶可以解旋底物，而实际上不会沿着PNA移位。
Helicases are ubiquitous enzymes involved in all aspects of DNA metabolism including replication, repair, recombination, and transcription. The mechanism of the bacteriophage T4 Dda helicase was investigated by preparing a DNA–PNA chimeric substrate. Surprisingly, Dda was able to unwind a substrate containing 12 PNA moieties in the loading strand of the enzyme. We suggest a mechanism whereby the Dda helicase contains two distinct DNA binding domains which allow an inchworm mechanism for translocation. A single step of the enzyme is sufficient to unwind the DNA–PNA chimera because several base pairs melt spontaneously due to thermal fraying. Hence, Dda helicase can unwind the substrate without actually translocating along the PNA.