Genetically-encoded libraries of peptide derivatives

我的研究项目的重点是从多肽中提取的有机分子的基因编码库的合成和应用。我们利用它们来发现具有独特分子识别特性的药物挑战靶标和分子的结合配体。*拟议的工作旨在满足对具有药物样特性的新化学实体(NCE)日益增长的需求，并为发现治疗分子提供创新技术。化学修饰的多肽是一类很有前途的候选化合物。由于其小尺寸，多肽衍生物可以具有类似于小分子的组织渗透性，而遗传选择允许快速发现和优化这些分子。在NSERC DG的第一个周期中，我的实验室开发了一种平台技术，用于以基因编码的方式发现多肽衍生物。它是基于噬菌体展示的多肽库，通过多步、特定部位的有机反应进行修饰。利用我们的NSERC DG的第二个周期，我们将推进GE文库的合成和应用。*Aim 1将开发新的化学策略，将展示在噬菌体上的线性、遗传编码的多肽转化为双环结构。我们利用展示在噬菌体上的多肽作为有机合成的起始原料。如果化学反应没有破坏噬菌体，合成可以进行多个步骤，产生基因编码的产品。这些产物可以通过它们的DNA标签进行选择和鉴定，也可以通过扩增来重新生成起始材料。为了延长这些分子在循环中的寿命，我们将白蛋白的配体移植到这个文库上，并选择具有强大的白蛋白结合能力的大环。这项研究将为在学术和工业实验室中加速早期发现铅提供新的策略。*目标2将发现针对特定多肽序列亚型的反应：例如，某些有转折的多肽序列最有可能在环化反应中发生反应。通常，新反应的发现需要测试大量的多肽序列。我们将利用展示在噬菌体上的约109个不同的多肽文库来加速发现这种反应，并设计探针，仅对经过所需反应(这里：环化)的多肽进行共价标记，并允许它们从文库中分离。这项拟议的工作代表了反应方法论的一种重要的新方法。*访问庞大的GE分子库使一个风险但令人兴奋的基础项目成为可能，该项目旨在发现具有通过合理结构设计难以预测的功能特性的分子。目标3描述了应用这些文库寻找触发自动催化过程的新的光响应配体，例如冰核和模仿天然冰核蛋白在一种构象(顺式)而不是在另一种构象(反式)。

The focus of my research program is synthesis and application of genetically-encoded libraries of organic molecules derived from peptides. We employ them for discovery of binding ligands for pharmaceutically challenging targets and molecules with unique molecular-recognition properties.***The proposed work aims to fulfill the increasing need for new chemical entities (NCE) with drug-like properties and to provide innovative technology for the discovery of therapeutic molecules. Chemically-modified peptides are a promising class of such candidates. Due to their small size, peptide derivatives can have tissue permeability akin to that of small molecules, while genetic selection allows for rapid discovery and optimization of these molecules. In the 1st cycle of NSERC DG, my lab developed a platform technology for genetically-encoded discovery of peptide derivatives. It is based on phage-displayed peptide libraries that are modified through multi-step, site-specific organic reactions. Using our 2nd cycle of NSERC DG, we will advance both synthesis and utility of GE-libraries.***Aim 1 will develop new chemical strategies that convert linear, genetically-encoded peptides displayed on phage to bicyclic structures. We use peptides displayed on phage as starting materials for organic synthesis. If the chemical reaction does not destroy the phage, synthesis can proceed for multiple steps and yield products that are genetically-encoded. The products can be selected and identified by their DNA tag, or amplified to re-generate the starting materials. To improve the lifetime of such molecules in circulation, we will graft ligands for albumin onto this library and select macrocycles with potent albumin binding capacity. This research will provide new strategies for accelerated early lead discovery in academic and industrial labs.***Aim 2 will discover reactions that target unique subtypes of peptide sequences: for example certain peptide sequences that have turns are most likely to react in a cyclization reaction. Typically, discovery of new reactions requires testing of a vast number of peptide sequences. We will accelerate discovery of such reactions using libraries of ~109 diverse peptides displayed on phage and design probes that covalently tag only peptides that underwent the desired reaction (here: cyclization) and permit their separation from the library. The proposed work represents a significantly new approach to reaction methodology.***Access to vast GE-libraries of molecules enables a risky yet exciting fundamental project that aim to discover molecules with functional properties that are difficult to predict by rational structural design. Aim 3 describes application of these libraries to find new light-responsive ligands that trigger autocatalytic processes, such as ice nucleation and mimic natural ice-nucleating proteins in one conformation (cis) but not in the other (trans).***