Enzyme-instructed nanoscale assemblies for killing multidrug resistant bacteria

摘要 病原菌对常见抗生素的耐药率不断上升 成为现代社会最紧迫的全球医疗保健问题之一。迫切需要 针对多药耐药(MDR)细菌的新型抗菌剂。因为抵抗的主要原因是 是β-内酰胺酶(一种细菌特有的酶)来降解抗生素，这项拟议的工作将导致 对杀死细菌事件的抵抗力。也就是说，这项研究将开发出 响应于β-内酰胺酶原位(即在细菌表面)形成纳米级组件 可以杀死多药耐药细菌。这项工作的目标是探索酶指导的自组装--即， 酶催化和分子自组装的集成--作为一种范式转换的方法 发现和早期开发治疗由耐药细菌引起的感染的新疗法。 这一提议既是假设的，也是设计驱动的。我们假设，酶引导的自我组装，就像 一种独特的方法将阳离子多肽的纳米级组装定位在细菌上，将杀死多药耐药细菌。 我们过去的结果--β-内酰胺酶指导多肽的自组装，自组装的超短纳米纤维 阳离子多肽抑制生物膜，酶指导的自组装抑制细菌生长，以及 多价抗生素抑制多药耐药细菌-强烈支持这一假设。为了验证这一假设，我们 将设计在β-内酰胺酶作用下自组装的阳离子多肽，表征 多肽及其组装体的物理化学性质，并评价其抗菌活性 抗多药耐药细菌的纳米级组件。具体来说，我们将评估1)电荷平衡的影响 前体物，2)阳离子多肽侧链长度的影响，3)多肽的影响 用于杀灭多药耐药细菌的阳离子多肽纳米级组装上的阳离子多肽序列。 通过设计、合成和表征含有阳离子多肽前体的β-内酰胺和 评价相应阳离子多肽组装体对多药耐药的抗菌活性 细菌，我们预计这项研究将提高对抗菌治疗的基本理解， 为设计抗菌剂提供指导原则，并最终导致前所未有的方法 结合酶反应和分子自组装的抗菌药物开发。

ABSTRACT The increasing prevalence of drug-resistance among pathogenic bacteria to common antibiotics has become one of the most pressing global healthcare problems in modern society. There is an urgent need for novel antimicrobial agents against multidrug resistant (MDR) bacteria. Because the major cause of resistance is beta-lactamase (a bacteria-specific enzyme) to degrade antibiotics, the proposed work will turn the cause of resistance to the event of killing the bacteria. That is, this research will develop the precursors that are responsive to beta-lactamase for in-situ (i.e., on the surface of bacteria) formation of nanoscale assemblies that kill MDR bacteria. The goal of this work is to explore enzyme-instructed self-assembly—that is, the integration of enzymatic catalysis and molecular self-assembly—as a paradigm-shifting approach for the discovery and early development of novel therapies for treating infections caused by drug resistant bacteria. This proposal is both hypothesis and design driven. We hypothesize that enzyme-instructed self-assembly, as a unique way to localize the nanoscale assemblies of cationic peptides onto bacteria, will kill MDR bacteria. Our past results—beta-lactamase instructing self-assembly of peptides, self-assembled nanofibers of ultrashort cationic peptides inhibiting biofilms, enzyme-instructed self-assembly inhibiting bacterial growth, and multivalent antibiotics inhibiting MDR bacteria—strongly support the hypothesis. To validate the hypothesis, we will design cationic peptides that self-assemble upon the action of beta-lactamase, characterize the physiochemical properties of the peptides and their assemblies, and assess the antibacterial activities of the nanoscale assemblies against MDR bacteria. Specifically, we will evaluate 1) the effects of charge balance of the precursors, 2) the effects of side chain length of the cationic peptides, and 3) the effects of peptide sequence of the cationic peptides on the nanoscale assemblies of cationic peptides for killing MDR bacteria. By designing, synthesizing, and characterizing the β-lactam containing precursors of cationic peptides and evaluate the antibacterial activities of the corresponding assemblies of the cationic peptides against MDR bacteria, we anticipate that this research will improve fundamental understanding of antimicrobial therapy, provide guiding principles to design antibacterial agents, and ultimately lead to an unprecedented approach of antibacterial drug development that integrates enzymatic reactions and molecular self-assembly.