Yin Qingdian, You Shengping, Zhang Jiaxing, Qi Wei, Su Rongxin
Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China.
Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, PR China.
Bioresour Technol. 2022 Nov;364:128026. doi: 10.1016/j.biortech.2022.128026. Epub 2022 Sep 27.
The serious environmental pollution that came up with the continuously growing demand for polyethylene terephthalate (PET) has attracted global concern. The IsPETase which has shown the highest PET degradation activity under ambient temperature is a promising enzyme for PET biodegradation, while poor thermostability limited its practical application. Herein, an electrostatic interaction-based strategy was applied for rational design of IsPETase towards enhanced thermostability. The IsPETase variant displayed the highest T value of 56.4 °C and 3.6-times higher PET degradation activity. Molecular simulations demonstrated that the introduction of salt bridges stabilized the local structures, resulting in robust thermostability. Meanwhile, the IsPETase not only exhibited higher thermostability but also showed a 1.74-fold k increase towards mono-(2-hydroxyethyl) terephthalate, which ultimately achieved PET depolymerization to complete monomer TPA. Collectively, the electrostatic interaction-based strategy, together with the derived IsPETase variants, could help promote the bio-recycle of PET, reducing the severe global burden of PET waste.
随着对聚对苯二甲酸乙二酯（PET）需求的不断增长而出现的严重环境污染已引起全球关注。在环境温度下表现出最高PET降解活性的IsPETase是一种有前途的用于PET生物降解的酶，但其较差的热稳定性限制了其实际应用。在此，基于静电相互作用的策略被应用于对IsPETase进行合理设计以提高其热稳定性。IsPETase变体显示出最高56.4°C的T值和高3.6倍的PET降解活性。分子模拟表明，盐桥的引入稳定了局部结构，从而产生了强大的热稳定性。同时，IsPETase不仅表现出更高的热稳定性，而且对单（2-羟乙基）对苯二甲酸酯的k值增加了1.74倍，最终实现了PET解聚为完整单体TPA。总的来说，基于静电相互作用的策略以及衍生的IsPETase变体有助于促进PET的生物循环，减轻全球PET废物的严重负担。
