Directional mechanical stability of Bacteriophage φ29 motor's 3WJ-pRNA: Extraordinary robustness along portal axis.
Directional mechanical stability of Bacteriophage φ29 motor's 3WJ-pRNA: Extraordinary robustness along portal axis.
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噬菌体 phi 29 电机 3WJ-pRNA 的定向机械稳定性：沿门轴具有非凡的稳健性
DOI：
10.1126/sciadv.1601684
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发表时间：
2017-05
期刊：
影响因子：
13.6
通讯作者：
Li J
中科院分区：
文献类型：
--
作者：
Xu Z;Sun Y;Weber JK;Cao Y;Wang W;Jasinski D;Guo P;Zhou R;Li J
φ29电机的三通接头在同轴方向上具有超强的刚性，起到了有效的连杆作用。φ29噬菌体利用分子马达将DNA装入其衣壳，被认为是病毒、细菌和真核生物系统中最强大的机械装置之一。作为连接元件，前体RNA （pRNA）有效地连接连接器和φ29马达的atp酶（腺苷三磷酸酶）组件。在DNA包装过程中，这种pRNA需要在衣壳的门脉轴上承受巨大的压力——这种显著的稳定性是如何实现的还有待阐明。采用定向分子动力学和原子力谱相结合的方法研究了φ29电机三通结(3WJ) -pRNA的力学性能。3WJ表现出较强的抗拉伸性能，表明其具有超强的结构稳健性。然而，当外力作用于横向方向时，这种阻力就消失了。从分子的角度来看，我们证明了这种方向依赖的稳定性可以归因于两个Mg钳在pRNA的同轴方向上合作并产生机械阻力。我们的研究结果表明，3WJ的机械稳定性的不对称性质与其生物学功能交织在一起：沿着门脉轴增强的刚性可能是承受DNA凝聚引起的应变所必需的，而其他方向的灵活性应该有助于pRNA的组装及其与其他运动部件的关联。
φ29 motor’s three-way junction serves as an effective connecting rod through its superb rigidity in the coaxial direction. The molecular motor exploited by bacteriophage φ29 to pack DNA into its capsid is regarded as one of the most powerful mechanical devices present in viral, bacterial, and eukaryotic systems alike. Acting as a linker element, a prohead RNA (pRNA) effectively joins the connector and ATPase (adenosine triphosphatase) components of the φ29 motor. During DNA packing, this pRNA needs to withstand enormous strain along the capsid’s portal axis—how this remarkable stability is achieved remains to be elucidated. We investigate the mechanical properties of the φ29 motor’s three-way junction (3WJ)–pRNA using a combined steered molecular dynamics and atomic force spectroscopy approach. The 3WJ exhibits strong resistance to stretching along its coaxial helices, demonstrating its super structural robustness. This resistance disappears, however, when external forces are applied to the transverse directions. From a molecular standpoint, we demonstrate that this direction-dependent stability can be attributed to two Mg clamps that cooperate and generate mechanical resistance in the pRNA’s coaxial direction. Our results suggest that the asymmetric nature of the 3WJ’s mechanical stability is entwined with its biological function: Enhanced rigidity along the portal axis is likely essential to withstand the strain caused by DNA condensation, and flexibility in other directions should aid in the assembly of the pRNA and its association with other motor components.
影响因子：
17.1
作者：
Xiao, Feng;Cai, Ying;Wang, Joseph Che-Yen;Green, Dominik;Cheng, R. Holland;Demeler, Borries;Guo, Peixuan
通讯作者：
Guo, Peixuan