厦门大学吴川六团队报道了具有N端可扩展α-螺旋的二硫定向多环肽识别和激活G蛋白偶联受体。相关研究成果于2024年12月17日发表于国际顶尖学术期刊《美国化学会杂志》。

许多肽激素在与同源受体相互作用时采用长α-螺旋结构，但在未结合时通常表现出灵活的构象。目前仍缺乏能够稳定长α-螺旋而不破坏其与受体结合的策略，这阻碍了其生物应用和药物开发的进展。

该文中，研究人员提出了一种将合理设计与文库筛选相结合的方法，以创建和鉴定一种独特的二硫键导向的多环肽（DDMP）支架，该支架可以有效地稳定N端可延伸的α-螺旋，同时在二硫键配对和氧化折叠方面表现出卓越的效率。然后，这种DDMP支架被用于稳定胰高血糖素样肽-1（GLP-1）的α螺旋结构，从而产生一种强效的GLP-1受体（GLP-1R）激动剂，其α螺旋性和蛋白水解稳定性显著提高。

通过将外部α-螺旋结合到DDMP支架中，从而有效地保留天然的N-末端α-螺旋结构，同时将富含C-末端二硫键的结构域的广泛进化，以增强靶结合，正如DDMP稳定的GLP-1（g1:Ox）的产生所证明的那样。g1:Ox-GLP-1R与异三聚体Gs复合物的冷冻电子显微镜结构揭示了g1:Ox和GLP-1R之间强结合的分子基础。具体而言，DDMP部分与GLP-1R的细胞外结构域建立了额外的相互作用，这种相互作用在GLP-1的情况下是不存在的。

该项工作为设计治疗性肽和其他肽α-螺旋提供了一种新颖有效的方法，确保N端和C端区域对靶识别和激活都是必不可少的。

附：英文原文

Title: Disulfide-Directed Multicyclic Peptides with N-Terminally Extendable α-Helices for Recognition and Activation of G-Protein-Coupled Receptors

Author: Shihui Fan, Jie Li, Jie Zhuang, Qingtong Zhou, Yiting Mai, Bingni Lin, Ming-Wei Wang, Chuanliu Wu

Issue&Volume: December 17, 2024

Abstract: Many peptide hormones adopt long α-helical structures upon interacting with their cognate receptors but often exhibit flexible conformations when unbound. Strategies that can stabilize long α-helices without disrupting their binding to receptors are still lacking, which hinders progress in their biological applications and drug development. Here, we present an approach that combines rational design with library screening to create and identify a unique disulfide-directed multicyclic peptide (DDMP) scaffold, which could effectively stabilize N-terminally extendable α-helices while displaying exceptional efficiency in disulfide pairing and oxidative folding. This DDMP scaffold was then utilized for stabilizing the α-helical structure of glucagon-like peptide-1 (GLP-1), resulting in a potent GLP-1 receptor (GLP-1R) agonist with a significantly improved α-helicity and proteolytic stability. By incorporating external α-helices into the DDMP scaffold, we can effectively preserve the native N-terminal α-helical structures while allowing for extensive evolution of the C-terminal disulfide-rich domain for enhancing target binding, as demonstrated by the generation of the DDMP-stabilized GLP-1 (g1:Ox). The cryo-electron microscopy structure of the g1:Ox–GLP-1R in complex with heterotrimeric Gs reveals the molecular basis for the potent binding between g1:Ox and GLP-1R. Specifically, the DDMP moiety establishes additional interactions with the extracellular domain of GLP-1R, which are absent in the case of GLP-1. Thus, this work offers a novel and effective approach for engineering therapeutic peptides and other peptide α-helices, ensuring that both the N- and C-terminal regions remain essential for target recognition and activation.

DOI: 10.1021/jacs.4c12808

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c12808