The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China.
Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China.
Biochemistry. 2021 Mar 23;60(11):886-897. doi: 10.1021/acs.biochem.0c00935. Epub 2021 Mar 9.
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.
生物马达在生命系统中无处不在，它们将化学能转化为各种机械运动，这些运动对细胞功能至关重要。噬菌体 φ29 中的基因产物 16（gp16）是已知的最强大的生物马达之一，它采用多亚基环形结构，通过水解 ATP 将双链 DNA（dsDNA）包装到预先形成的衣壳中。在这里，我们报告了 gp16 的 C 末端结构域（gp16-CTD）的晶体结构。基于结构的比对和分子动力学模拟揭示了 gp16-CTD 与头部 RNA 之间的一个重要结合表面，头部 RNA 是马达复合物的独特组成部分。此外，我们的模拟突出了 gp16 的 N 末端结构域和 CTD 之间的动态相互作用，这可能在驱动 DNA 进入衣壳的过程中发挥作用。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 φ29 dsDNA 包装马达复合物的原子结构模型。总的来说，我们的发现为 φ29 噬菌体 dsDNA 转位提供了一个精细化的尺蠖-蠕动模型，并提出了 gp16 的各个结构域如何协同作用以实现这种转位。
