Synthesis and discovery of biologically active cell-permeable cyclic peptides

描述(由申请人提供)：环肽已被探索为针对多种生物靶标的配体。它们相对容易合成，同时显示出大多数其他类别的小分子所无法比拟的复杂程度。然而，环肽通常具有细胞通透性差的问题，这是一般多肽的共同特征。事实上，药物开发的一个关键瓶颈在于无法预测和控制控制小分子细胞渗透性的因素。我们研究计划的全球目标是创造新一代具有生物活性、细胞透过性的环肽作为探针和先导抗生素和抗真菌化合物。在这个建议中，我们试图通过测试关于主链构象、环大小和侧链功能对环肽被动膜扩散的影响的假设来扩大我们对这类重要化合物的膜通透性的理解。从天然产物中吸取教训，环肽中的细胞渗透性通常由关键修饰决定--即一个或多个多肽酰胺的N-甲基化--这有助于将极性骨架运输到疏水脂质双层上。在这里，我们应用了一种强大的新方法来进行区域选择性N-甲基化来生成环肽文库，这些文库显示出比非甲基化对应物更好的膜通透性。此外，我们还将开发一种环状和线状多肽的磺化策略，生成生物可逆前药，与其未经修饰的母体化合物相比，膜通透性有很大改善。最后，我们在酵母、细菌(霍乱弧菌)和哺乳动物细胞中建立了一组高通量的表型筛选，以寻找调节各种生物过程的化合物。使用前三个目标中开发的方法，我们将生成天然产物启发的、膜渗透环肽的库，用于输入到这些屏幕中，最终结果是一系列强大的生物活性化合物，为进一步开发做好准备。 与公众健康相关：我们研究计划的总体目标是了解小分子膜通透性的结构基础。我们建议使用环肽作为分子支架来研究通透性的构象基础，并应用我们所学到的知识来创造新一代生化探针。我们将计算方法与合成有机化学和高通量筛选相结合，开发了一类受天然产物启发的新型生物活性环肽。我们预计这个项目将会出现新的抗生素和抗真菌药物。

DESCRIPTION (provided by applicant): Cyclic peptides have been explored as ligands against a wide variety of biological targets. They are relatively easy to synthesize, and, at the same time, exhibit a degree of complexity unrivaled by most other classes of small molecules. However, cyclic peptides often suffer from poor cell permeability, a characteristic common to peptides in general. Indeed, a key bottleneck in drug development lies in the inability to predict and control factors that govern cell permeability in small molecules. The global objective of our research program is to create a new generation of biologically active, cell permeable cyclic peptides as probes and lead antibiotic and antifungal compounds. In this proposal, we seek to broaden our understanding of membrane permeability in this important class of compounds by testing hypotheses regarding the influence on backbone conformation, ring size, and side chain functionality, on the passive membrane diffusion of cyclic peptides. Taking a lesson from natural products, cell permeability in cyclic peptides is often determined by key modification - namely, N-methylation of one or more peptide amides - that help to transport the polar backbone across the hydrophobic lipid bilayer. Here we apply a powerful new approach to regioselective N-methylation to generate libraries of cyclic peptides that exhibit improved membrane permeability over their non-methylated counterparts. In addition, we will develop a strategy for the sulfenylation of cyclic and linear peptides, generating bioreversible prodrugs with greatly improved membrane permeability relative to their unmodified parent compounds. Finally, we have put in place a panel of high-throughput phenotypic screens in yeast, bacteria (V. cholera), and mammalian cells for compounds that modulate a wide variety of biological processes. Using the methods developed in the first three aims, we will generate libraries of natural product-inspired, membrane permeable cyclic peptides for input into these screens, with the end result being a collection of potent bioactive compounds poised for further development. PUBLIC HEALTH RELEVANCE: The overall objective of our research program is to understand the structural basis of membrane permeability in small molecules. We propose to use cyclic peptides as molecular scaffolds to study the conformational basis of permeability, and apply what we learn to create a new generation of biochemical probes. We combine computational approaches with synthetic organic chemistry and high-throughput screening to develop a new class of bioactive cyclic peptides inspired by natural products. We expect that new antibiotics and antifungal agents will emerge from this project.