Effects of Hydrostatic Pressure on the Thermodynamics of CspB-Bs Interactions with the ssDNA Template
Effects of Hydrostatic Pressure on the Thermodynamics of CspB-Bs Interactions with the ssDNA Template
复制标题
静水压力对 CspB-Bs 与 ssDNA 模板相互作用热力学的影响
DOI：
10.1021/acs.biochem.1c00561
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发表时间：
2021
期刊：
影响因子：
2.9
通讯作者：
Makhatadze, George I.
中科院分区：
文献类型：
--
作者：
Avagyan, Samvel;Makhatadze, George I.
了解生物大分子适应高静水压力的热力学机制可以帮助阐明嗜压生物如何在超过1000个大气压的压力下生存。蛋白质与核酸的相互作用是允许在DNA序列中编码的信息流的中心过程之一。本文报道了枯草芽孢杆菌冷休克蛋白B（CspB-Bs）与七脱氧胸腺嘧啶模板（pDT 7）相互作用的研究结果。使用解释蛋白质解折叠和CspB-Bs：pDT 7结合的热力学连接模型分析在不同CspB-Bs：pDT 7比率下收集的实验数据。模型的全局拟合提供了CspB-Bs稳定性的估计值ΔGProto、CspB-Bs解折叠时的体积变化ΔVProt、CspB-Bs：pDT 7复合物的缔合常数Kao和pDT 7单链DNA（ssDNA）模板结合时的体积变化ΔVBind。蛋白质CspB-Bs随着流体静压的增加而展开（ΔVProt< 0）。令人惊讶的是，我们的研究表明ΔVBind< 0，这意味着CspB-Bs与ssDNA的结合通过静水压力的增加而稳定。因此，CspB-Bs与pDT 7的结合代表了连锁平衡的情况，其中折叠和结合在流体静压力增加时反应不同：蛋白质折叠/解折叠平衡有利于解折叠状态，而蛋白质-配体结合平衡有利于结合状态。这些相反的作用为蛋白质-ssDNA复合物在给定条件下设定了“可达到的最大”压力耐受性。
Understanding the thermodynamic mechanisms of adaptation of biomacromolecules to high hydrostatic pressure can help shed light on how piezophilic organisms can survive at pressures reaching over 1000 atmospheres. Interaction of proteins with nucleic acids is one of the central processes that allow information flow encoded in the sequence of DNA. Here, we report the results of a study on the interaction of cold shock protein B fromBacillus subtilis(CspB-Bs) with heptadeoxythymine template (pDT7) as a function of temperature and hydrostatic pressure. Experimental data collected at different CspB-Bs:pDT7 ratios were analyzed using a thermodynamic linkage model that accounts for both protein unfolding and CspB-Bs:pDT7 binding. The global fit to the model provided estimates of the stability of CspB-Bs, ΔGProto, the volume change upon CspB-Bs unfolding, ΔVProt, the association constant for CspB-Bs:pDT7 complex,Kao, and the volume changes upon pDT7 single-stranded DNA (ssDNA) template binding, ΔVBind. The protein, CspB-Bs, unfolds with an increase in hydrostatic pressure (ΔVProt< 0). Surprisingly, our study showed that ΔVBind< 0, which means that the binding of CspB-Bs to ssDNA is stabilized by an increase in hydrostatic pressure. Thus, CspB-Bs binding to pDT7 represents a case of linked equilibrium in which folding and binding react differently upon an increase in hydrostatic pressure: protein folding/unfolding equilibrium favors the unfolded state, while protein–ligand binding equilibrium favors the bound state. These opposing effects set a “maximum attainable” pressure tolerance to the protein–ssDNA complex under given conditions.