Genetically-encoded libraries of peptide derivatives

我的研究项目的重点是合成和应用的遗传编码库的有机分子来源于肽。我们使用它们来发现具有独特分子识别特性的药物挑战性靶标和分子的结合配体。*这项工作旨在满足对具有药物样性质的新化学实体（NCE）日益增长的需求，并为发现治疗分子提供创新技术。化学修饰的肽是一类有前途的候选物。由于它们的小尺寸，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，用于发现肽衍生物的遗传编码。它是基于噬菌体展示肽库，通过多步，位点特异性有机反应进行修饰。使用我们的NSERC DG的第二个周期，我们将推进GE文库的合成和实用性。目标1将开发新的化学策略，将噬菌体上展示的线性、遗传编码的肽转化为双环结构。我们使用展示在噬菌体上的肽作为有机合成的起始材料。如果化学反应不破坏噬菌体，合成可以进行多个步骤，并产生遗传编码的产物。可以通过其DNA标签选择和鉴定产物，或者扩增以再生起始材料。为了提高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库上，并选择具有有效的白蛋白结合能力的大环化合物。这项研究将为加速学术和工业实验室的早期铅发现提供新的策略。目标2将发现靶向肽序列的独特亚型的反应：例如，具有转角的某些肽序列最有可能在环化反应中反应。通常，发现新的反应需要测试大量的肽序列。我们将使用噬菌体上展示的~109种不同肽的文库加速发现此类反应，并设计仅共价标记经历所需反应（此处：环化）的肽并允许其从文库中分离的探针。这项工作代表了一种重要的新的反应方法。访问庞大的GE分子库可以实现一个风险但令人兴奋的基础项目，旨在发现具有难以通过合理结构设计预测的功能特性的分子。目标3描述了这些库的应用，以发现新的光响应配体，其触发自催化过程，例如冰成核和模拟天然冰成核蛋白的一种构象（顺式）而不是另一种构象（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).***