Site-selective functionalisation of peptides and proteins via free-radical-induced dechalcogenation

化学的发展使研究人员能够用一系列功能性分子“标签”修饰蛋白质的特定位置，这有可能产生重大的科学影响。将这类技术应用于以蛋白质为基础的“生物”药物的修饰，有助于开发更有效的疾病治疗方法，这类药物目前在制药市场上占主导地位。在基础科学的背景下，携带自然发生修饰的蛋白质的制备为询问生物途径提供了工具，并使人们能够更好地理解细胞生物化学。因此，生物偶联技术在世界各地的学术和工业实验室中被常规使用。本提案描述了一种新的和通用的蛋白质功能化方法的发展，它比目前的方法提出了进步。由于蛋白质特有的化学性质，对这些生物分子进行修饰的合成方法必须在特定的条件下进行。成功的生物偶联反应在室温下的水中进行，在低浓度下产生高产率，并对21种天然存在的（典型）氨基酸残基中的一种表现出选择性。遵循该模板的反应可以在不降解氨基酸序列或形成不需要的副产物的情况下修饰目标蛋白。考虑到这些方面，我们开发了一种新颖，高效和选择性的反应，可以针对两种天然氨基酸进行调整；半胱氨酸和硒型半胱氨酸。该方法快速、定量、可持续，在理想的蛋白质化学条件下进行。该方案不需要贵金属催化剂或昂贵/不稳定的试剂，操作简单，允许跨科学学科应用，最大限度地发挥化学和生物科学的影响。这项新研究者奖将使我们能够建立一个多学科团队，专注于我们新的合成平台的开发和应用。设想使用这种方法可以将广泛的功能安装到感兴趣的蛋白质中；将评估包括用于医学成像的造影剂、用于治疗的药物偶联物和用于促进复杂生物过程调查的反应性标签或天然蛋白质修饰。用化学基团修饰的蛋白质将能够进一步研究蛋白质降解和靶向、成像和治疗高度侵袭性癌症的工具，也将在该项目的职权范围内交付。此外，此次合作将使我们能够在诺丁汉大学化学学院建立蛋白质生物偶联的专业知识、技术和培训基础。新的多功能化学的发展，可以应用于将一系列功能基团安装到蛋白质中，以适应许多特定的应用，将是对研究人员目前可用的方法的有力补充。

The development of chemistry that enables researchers to decorate proteins at defined positions with a range of functional molecular 'tags' has the potential to generate significant scientific impact. The application of such techniques to the modification of protein-based 'biologic' drugs, a class that currently dominates the pharmaceutical market, facilitates the development of more effective treatments for disease. Within the context of fundamental science, the preparation of proteins that carry naturally occurring modifications provides tools to interrogate biological pathways and enable a greater understanding of cellular biochemistry. As a result, bioconjugate techniques are used routinely in academic and industrial labs across the world. This proposal describes the development of a novel and versatile approach to protein functionalisation that presents advances over current methods.Due to the characteristic chemical properties of proteins, synthetic methods that facilitate modification of these biological molecules must operate under a specific set of conditions. Successful bioconjugation reactions proceed in water at ambient temperature, afford high yield at low concentrations and demonstrate selectivity for one of the 21 naturally occurring (canonical) amino acid residues. Reactions that follow this template enable modification of a target protein without degradation of the amino acid sequence or the formation of undesired by-products. With these aspects in mind, we have developed a novel, efficient and selective reaction that can be tuned to target two natural amino acids; cysteine and selenocysteine. The method is rapid, quantitative and sustainable, proceeding under conditions ideal for protein chemistry. The protocol requires no precious metal catalyst or costly/unstable reagents and is operationally simple, allowing application across scientific disciplines to maximise impact within the chemical and biological sciences. This New Investigator Award will enable us to establish a multidisciplinary team focused on the development and application of our new synthetic platform. It is envisaged that a broad range of functionality could be installed into a protein of interest using this approach; the inclusion of contrast agents for medical imaging, drug-conjugates for therapy and reactive tags or natural protein modifications to facilitate the investigation of complex biological processes will be evaluated. Proteins modified with chemical groups that will enable further investigation of protein degradation and tools to target, image and treat highly invasive forms of cancer will also be delivered within the remit of this project. Furthermore, this collaboration will enable us to establish a base of expertise, technology, and training in protein bioconjugation within the School of Chemistry, University of Nottingham.The development of new, versatile chemistry that can be applied to install a range of functional groups into a protein, to suit many specific applications, would be a powerful addition to the methodology currently available to researchers.