Ampetoids as Biostable Functional Mimics of Antimicrobial Peptides

描述（由申请人提供）：我们建议创建和研究一个新的仿生低聚物家族，用于抗菌应用。特别是，我们的目标是创造生物稳定的，天然抗菌肽（AMP），这是从人类到细菌的无数生物体的宿主防御系统的一个组成部分和有效的功能模拟。通过优先结合并破坏或渗透细菌细胞膜，这些表面活性肽能够杀死广谱微生物。许多也是选择性的，不会对哺乳动物细胞造成伤害。杀伤机制，虽然不完全理解，是足够普遍的细菌已经无法进化耐药性抗菌肽数百万年。因此，抗菌肽的良好功能模拟物有望成为一类新型抗生素化合物，它们可以直接在溶液中发挥作用，也可以固定在生物医学设备的表面以避免感染。我们建议创建AMP的非天然模拟物，因为肽本身易受蛋白水解的影响，因此在体内降解得太快，而且因为肽在体内通常具有免疫原性。特别是，我们的新型模拟物将基于两亲性的、序列特异性的寡-N-取代的甘氨酸（“类肽”）。类肽在结构上与肽非常相似，但具有蛋白酶抗性。它们很容易通过高产的固相方案合成，该方案允许容易地掺入仿生侧链。此外，类肽可以被设计成形成稳定的仿生螺旋，其在水和生物膜环境中保持其折叠结构，并且其对变性具有高度抗性。在初步工作中，我们已经表明，某些拟肽序列（9- 17聚体）被设计成模拟抗菌肽的两亲性序列模式和螺旋结构，是有效的和选择性的抗菌剂（对大肠杆菌的MIC ~ 4 μ M）。大肠杆菌和820 nM对B. subtilis，在E. coli MIC）。我们建议进一步研究和开发这些化合物，通过（1）通过对具有不同效力/选择性特征的密切相关的类肽的“基组”的详细生物物理研究来探索结构-功能关系和作用机制，（2）产生模拟天然AMP的结构基序的新型类肽，包括脂化、环化和扭结的类肽;（3）测试它们对抗药性细菌的抗生素活性以及它们对人类细胞的毒性的早期研究。

DESCRIPTION (provided by applicant): We propose to create and study a new family of biomimetic oligomers for antibacterial applications. In particular, we aim to create biostable, functional mimics of natural antimicrobial peptides (AMPs), which are an integral and effective part of the host-defense systems of myriad organisms ranging from humans to bacteria. By preferentially binding to and disrupting or permeating bacterial cell membranes, these surface- active peptides are able to kill a broad spectrum of microorganisms. Many are also selective, causing no harm to mammalian cells. The killing mechanism, while imperfectly understood, is sufficiently general that bacteria have been unable to evolve resistance to AMPs over millions of years. Thus, good functional mimics of AMPs hold forth the promise of serving as a new class of antibiotic compounds, which could act in solution directly or be tethered to the surfaces of biomedical devices to stave off infection. We propose to create non-natural mimics of AMPs, since peptides themselves are vulnerable to proteolysis and hence degrade too rapidly in the body, and moreover because peptides are often immunogenic in vivo. In particular, our novel mimics will be based on amphipathic, sequence-specific oligo-N-substituted glycines ("peptoids"). Peptoids are quite similar in structure to peptides, yet are protease-resistant. They are easily synthesized by a high-yielding, solid-phase protocol that allows the easy incorporation of biomimetic side chains. Moreover, peptoids can be designed to form stable, biomimetic helices that keep their folded structure in both aqueous and biomembrane environments, and which are highly resistant to denaturation. In preliminary work, we have shown that certain peptoid sequences (9-17mers) designed to mimic the amphipathic sequence patterning and helical structure of antimicrobial peptides are potent and selective antibacterials (MIC ~ 4 ¿M against E. coli and 820 nM against B. subtilis, with negligible hemolysis at the E. coli MIC). We propose to further study and develop these compounds, by (1) exploring structure-function relationships and mechanism(s) of action through detailed biophysical studies of a "basis set" of closely related peptoids with differing potency/selectivity profiles, (2) creating novel peptoids that mimic structural motifs of natural AMPs, including peptoids that are lipidated, cyclized, and kinked; (3) testing their antibiotic activity against antibiotic-resistant bacteria as well as early-stage investigation of their toxicity to human cells.