Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Chembiochem. 2019 Nov 18;20(22):2834-2840. doi: 10.1002/cbic.201900300. Epub 2019 Sep 20.
Family B G protein-coupled receptors play important physiological roles and possess large extracellular domains (ECDs) that aid in binding the long polypeptide hormones that are their natural agonists. We have previously shown that agonist analogues in which subsets of native α-amino acid residues are replaced with β-amino acid residues can retain activity while avoiding proteolytic degradation. This study focuses on eight new α/β analogues of glucagon-like peptide 1 (GLP-1) that each contain five α-to-β replacements in the C-terminal half of the peptide. This portion of GLP-1 is known to adopt an α-helical conformation and contact the ECD. All four registries of the αααβ backbone pattern were evaluated; previous work has shown that the αααβ pattern supports adoption of an α-helix-like conformation. Two α-to-β replacement formats were employed, one involving β homologues of the native residues replaced and the other involving a cyclic β residue. GLP-1R response was characterized in terms of stimulation of cAMP production and β-arrestin recruitment. Some of the backbone-modified GLP-1 analogues display biased agonism of the GLP-1R. This study helps to establish the scope of the α→β backbone modification strategy.
家族 B G 蛋白偶联受体发挥着重要的生理作用,并且拥有大的细胞外结构域(ECD),有助于结合它们的天然激动剂——长多肽激素。我们之前已经表明,其中一部分天然α-氨基酸残基被β-氨基酸残基取代的激动剂类似物可以保留活性,同时避免蛋白水解降解。本研究集中于 8 种新的胰高血糖素样肽 1(GLP-1)的α/β类似物,它们每个都在肽的 C 端的一半包含五个α到β的取代。已知 GLP-1 的这一部分采用α-螺旋构象并与 ECD 接触。评估了所有四个αααβ骨架模式的登记册;以前的工作表明,αααβ模式支持采用α-螺旋样构象。使用了两种α到β的替换格式,一种涉及取代天然残基的β类似物,另一种涉及环状β残基。以 cAMP 产生和β-arrestin 募集的刺激来表征 GLP-1R 的反应。一些骨干修饰的 GLP-1 类似物显示出 GLP-1R 的偏激动作用。这项研究有助于确定α→β骨干修饰策略的范围。