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Abstract：
Biological motors, ubiquitous in living systems, convert chemical energy into different kinds of mechanical motions critical to cellular functions. Gene product 16 (gp16) in bacteriophage ϕ29 is among the most powerful biomotors known, which adopts a multisubunit ring-shaped structure and hydrolyzes ATP to package double-stranded DNA (dsDNA) into a preformed procapsid. Here we report the crystal structure of the C-terminal domain of gp16 (gp16-CTD). Structure-based alignment and molecular dynamics simulations revealed an essential binding surface of gp16-CTD for prohead RNA, a unique component of the motor complex. Furthermore, our simulations highlighted a dynamic interplay between the N-terminal domain and the CTD of gp16, which may play a role in driving movement of DNA into the procapsid. Lastly, we assembled an atomic structural model of the complete ϕ29 dsDNA packaging motor complex by integrating structural and experimental data from multiple sources. Collectively, our findings provided a refined inchworm-revolution model for dsDNA translocation in bacteriophage ϕ29 and suggested how the individual domains of gp16 work together to power such translocation.
摘要：
生物马达,在生命系统中无处不在，将化学能转化为对细胞功能至关重要的不同类型的机械运动。噬菌体φ29中的基因产物16（gp16）是已知的最强大的生物细胞之一，它采用多亚基环状结构并水解ATP以将双链DNA（dsDNA）包装成预先形成的原衣壳。在这里，我们报告了gp16（gp16-CTD）的C末端结构域的晶体结构。基于结构的比对和分子动力学模拟揭示了proheadRNA的gp16-CTD的基本结合表面，电机复杂的一个独特的组成部分。此外，我们的模拟强调了gp16的N端结构域和CTD之间的动态相互作用,这可能在驱动DNA移动到前衣壳中起作用.最后,我们通过整合来自多个来源的结构和实验数据，组装了完整的Φ29dsDNA包装马达复合物的原子结构模型。总的来说，我们的发现为噬菌体φ29中的dsDNA易位提供了一个完善的虫革命模型，并提出了gp16的单个结构域如何协同工作来推动这种易位。
