Lin Wei, Zheng Yunxin, Zhang Jiaxing, Zhou Yu, Wang Mengfan, You Shengping, Su Rongxin, Qi Wei
Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.
School of Life Sciences, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, PR China; Yuantian Biotechnology (Tianjin) Co., Ltd, PR China.
J Hazard Mater. 2025 Jun 15;490:137837. doi: 10.1016/j.jhazmat.2025.137837. Epub 2025 Mar 5.
The accumulation of polyethylene terephthalate (PET) waste has caused significant environmental pollution. Although biological depolymerization offers a promising solution, its efficiency remains constrained by the limited activity of PET-degrading enzymes. In this study, we designed a Structure-guided Loop-focused Iterative Mutagenesis (SLIM) strategy and rationally engineered the PET degradation enzyme ICCG for higher activity. The strategy was designed by demonstrating the critical role of the β8-α6 loop in type Ⅰ enzymes, which has currently not been reported. The best variant obtained, YITA (H183Y/L202I/I208T/T153A), exhibited 4.46-fold higher hydrolytic activity on amorphous PET at 72 °C compared to ICCG, outperforming other PET hydrolases, and exhibited superior degradation activity on real substrates such as cake containers and PET fibers. Conformational analysis revealed the key role of the remodeled β8-α6 loop in substrate binding and overall stability. Collectively, this study explores a promising approach to modifying PET hydrolase and lays a theoretical foundation for advancing bio-circular economy.
聚对苯二甲酸乙二酯（PET）废弃物的积累已造成严重的环境污染。尽管生物解聚提供了一个有前景的解决方案，但其效率仍受限于PET降解酶的有限活性。在本研究中，我们设计了一种基于结构导向的环聚焦迭代诱变（SLIM）策略，并对PET降解酶ICCG进行合理改造以提高其活性。该策略是通过证明β8-α6环在Ⅰ型酶中的关键作用而设计的，目前尚未有相关报道。获得的最佳变体YITA（H183Y/L202I/I208T/T153A）在72℃下对非晶态PET的水解活性比ICCG高4.46倍，优于其他PET水解酶，并且在蛋糕容器和PET纤维等实际底物上表现出优异的降解活性。构象分析揭示了重塑的β8-α6环在底物结合和整体稳定性中的关键作用。总的来说，本研究探索了一种有前景的修饰PET水解酶的方法，并为推进生物循环经济奠定了理论基础。
