Abstract：
Polyethylene terephthalate (PET), the most abundant polyester plastic, has become a global concern due to its refractoriness and accumulation in the environment. In this study, inspired by the structure and catalytic mechanism of the native enzyme, peptides, based on supramolecular self-assembly, were developed to construct enzyme mimics for PET degradation, which were achieved by combining the enzymatic active sites of serine, histidine and aspartate with the self-assembling polypeptide MAX. The two designed peptides with differences in hydrophobic residues at two positions exhibited a conformational transition from random coil to β-sheet by changing the pH and temperature, and the catalytic activity followed the self-assembly \"switch\" with the fibrils formed β-sheet, which could catalyze PET efficiently. Although the two peptides possessed same catalytic site, they showed different catalytic activities. Analysis of the structure - activity relationship of the enzyme mimics suggested that the high catalytic activity of the enzyme mimics for PET could be attributed to the formation of stable fibers of peptides and ordered arrangement of molecular conformation; in addition, hydrogen bonding and hydrophobic interactions, as the major forces, promoted effects of enzyme mimics on PET degradation. Enzyme mimics with PET-hydrolytic activity are a promising material for degrading PET and reducing environmental pollution.
摘要：
聚对苯二甲酸乙二醇酯(PET),最丰富的聚酯塑料，由于其在环境中的不变性和积累，已成为全球关注的问题。在这项研究中,受天然酶的结构和催化机理的启发，肽，基于超分子自组装，被开发用于构建PET降解的酶模拟物，这是通过结合丝氨酸的酶活性位点来实现的，组氨酸和天冬氨酸与自组装多肽MAX。通过改变pH和温度，在两个位置具有疏水性残基差异的两种设计肽表现出从无规卷曲到β折叠的构象转变，催化活性跟随自组装“转换”，原纤维形成β-折叠，这可以有效地催化PET。虽然这两种肽具有相同的催化位点,它们表现出不同的催化活性。酶模拟物的结构-活性关系分析表明，酶模拟物对PET的高催化活性可能归因于肽稳定纤维的形成和分子构象的有序排列；此外，氢键和疏水相互作用，作为主要力量，酶模拟物对PET降解的促进作用。具有PET水解活性的酶模拟物是降解PET和减少环境污染的有前途的材料。
