Translocation of viral double-stranded DNA (dsDNA) into the icosahedral prohead shell is catalyzed by TerL, a motor protein that has ATPase, endonuclease, and translocase activities. TerL, following endonucleolytic cleavage of immature viral DNA concatemer recognized by TerS, assembles into a pentameric ring motor on the prohead's portal vertex and uses ATP hydrolysis energy for DNA translocation. TerL's N-terminal ATPase is connected by a hinge to the C-terminal endonuclease. Inchworm models propose that modest domain motions accompanying ATP hydrolysis are amplified, through changes in electrostatic interactions, into larger movements of the C-terminal domain bound to DNA. In phage ϕ29, four of the five TerL subunits sequentially hydrolyze ATP, each powering translocation of 2.5 bp. After one viral genome is encapsidated, the internal pressure signals termination of packaging and ejection of the motor. Current focus is on the structures of packaging complexes and the dynamics of TerL during DNA packaging, endonuclease regulation, and motor mechanics.

中文翻译：

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大型双链 DNA 病毒的 DNA 包装机制。

病毒双链 DNA (dsDNA) 易位到二十面体前壳是由 TerL 催化的，TerL 是一种具有 ATP 酶、核酸内切酶和转位酶活性的运动蛋白。TerL，在被 TerS 识别的未成熟病毒 DNA 多联体的内切核酸裂解后，在前头的门户顶点上组装成一个五聚体环马达，并使用 ATP 水解能量进行 DNA 易位。TerL 的 N 端 ATP 酶通过铰链连接到 C 端核酸内切酶。Inchworm 模型提出伴随 ATP 水解的适度域运动被放大，通过静电相互作用的变化，进入与 DNA 结合的 C 端域的更大运动。在噬菌体 ϕ29 中，五个 TerL 亚基中的四个依次水解 ATP，每个亚基为 2.5 bp 的易位提供动力。一个病毒基因组被包裹后，内部压力发出包装结束和电机顶出的信号。目前的重点是在 DNA 包装、核酸内切酶调节和运动力学过程中包装复合物的结构和 TerL 的动力学。