DNA Heats Up: Energetics of Genome Ejection from Phage Revealed by Isothermal Titration Calorimetry
DNA Heats Up: Energetics of Genome Ejection from Phage Revealed by Isothermal Titration Calorimetry
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DOI：
10.1016/j.jmb.2009.11.069
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发表时间：
2010-02-05
影响因子：
5.6
通讯作者：
Evilevitch, Alex
中科院分区：
文献类型：
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作者：
Jeembaeva, Meerim;Jonsson, Bengt;Evilevitch, Alex
已知大多数噬菌体在受体结合后以一种本质上自发的方式将其双链DNA注入细菌。从完整的病毒粒子到空的病毒衣壳加上释放的DNA的下速热力学过程，是通过将基因组主动包装到衣壳中所储存的能量而成为可能的。到目前为止，只能使用单分子或渗透抑制技术间接测量这种能量。在这项工作中，我们首次描述了使用等温滴定量热法直接测量DNA从噬菌体λ喷射时释放的热量（或等效的焓），这是由溶解受体在溶液中触发的。定量分析结果导致鉴定与DNA喷射相关的热力学决定因素。得到的数值与先前通过解析模型和数值模拟预测的结果一致。此外，这些结果证实了DNA水合作用在病毒衣壳中基因组限制的能量学中的作用。2009爱思唯尔有限公司版权所有
Most bacteriophages are known to inject their double-stranded DNA into bacteria upon receptor binding in an essentially spontaneous way. This downhill thermodynamic process from the intact virion to the empty viral capsid Plus released DNA is made possible by the energy stored during active packaging of the genome into the capsid. Only indirect measurements of this energy have been available until now, using either single-molecule or osmotic suppression techniques. In this work, we describe for the first time the use of isothermal titration calorimetry to directly measure the heat released (or, equivalently, the enthalpy) during DNA ejection from phage lambda, triggered in solution by a solubilized receptor. Quantitative analyses of the results lead to the identification of thermodynamic determinants associated with DNA ejection. The values obtained were found to be consistent with those previously predicted by analytical models and numerical simulations. Moreover, the results confirm the role of DNA hydration in the energetics of genome confinement in viral capsids. (C) 2009 Elsevier Ltd. All rights reserved