Polyethylene terephthalate (PET) is the most abundant plastic waste in the environment. Currently, a new biocatalyst PETase, was discovered in 2016 from Ideonella sakaiensis bacteria, owned the high ability to digest PET through a mild and sustainable process. However, the high-level production of PETase in the model Escherichia coli remains a challenge and limits its application. Therefore, we employ the native molecular chaperones from Ideonella sakaiensis to improve the quality and quantity of an outstanding PETase variant, FAST-PETase (FA) at the first time. We selected GroELS from E. coli (EcG) and I. sakaiensis (IsG) using three genetic designs while the co-expressing FA with IsG chaperone increased soluble FA and elevated its activity by 25%. On the other hand, through the genome mining of I. sakaiensis, we identified a lipase secretion chaperone (IsLsC) at the upstream of native PETase. When co-expressing IsLsC and FA, the degradation efficiency toward PET film was up to 51.7 % within one day at 50 °C. More LsC like chaperones can be explored from the sequence similarity network (SSN) with corresponding function to IsLsC. Finally, molecular docking and dynamic simulation exploited a hydrogen bond formation between FA and IsLsC to stabilizing the structure. The discovery of a novel chaperone offers a promising strategy for attractive PETase engaging in PET waste valorization.

中文翻译：

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开发和阐明伴侣辅助 PET 水解酶用于塑料升级回收


聚对苯二甲酸乙二醇酯 （PET） 是环境中最丰富的塑料垃圾。目前，2016 年从 Ideonella sakaiensis 细菌中发现了一种新的生物催化剂 PETase，它通过温和和可持续的过程具有消化 PET 的高能力。然而，在大肠杆菌模型中高水平生产 PETase 仍然是一个挑战，并限制了其应用。因此，我们采用来自 Ideonella sakaiensis 的天然分子伴侣来首次提高出色的 PETase 变体 FAST-PETase （FA） 的质量和数量。我们使用三种基因设计从大肠杆菌 （EcG） 和鸠虾 （IsG） 中选择了 GroELS，而与 IsG 伴侣共表达的 FA 增加了可溶性 FA 并将其活性提高了 25%。另一方面，通过对 I. sakaiensis 的基因组挖掘，我们在天然 PETase 的上游鉴定了一个脂肪酶分泌伴侣 （IsLsC）。当共表达 IsLsC 和 FA 时，在 50 °C 下，对 PET 薄膜的降解效率在 1 天内高达 51.7 %。 可以从序列相似性网络 （SSN） 中探索更多类似 LsC 的伴侣，并与 IsLsC 具有相应的功能。最后，分子对接和动力学模拟利用 FA 和 IsLsC 之间的氢键形成来稳定结构。新型伴侣的发现为有吸引力的 PETase 参与 PET 废物价值化提供了一种有前途的策略。