孤儿核雌激素相关受体γ（ERRγ）已被认为是癌症、炎症和代谢紊乱的潜在治疗靶点。 ERRγ 包含一个调节性 AF2 螺旋尾，C 端与其配体结合域 (LBD) 连接，LBD 是一种自结合肽 (SBP)，可作为分子开关，通过结合动态调节受体活性和非活性状态之间的交替。分别与 ERRγ LBD 表面上的 AF2 结合位点结合和解除结合。传统的ERRγ调节剂均为小分子化学配体，根据作用机制可分为激动剂和反激动剂；激动剂以激动剂构象稳定 ABS 位点中的 AF2，而反向激动剂将 AF2 锁定在该位点之外，从而很大程度上消除 ERRγ 转录活性。在此，一类 ERRγ 肽拮抗剂被描述为与天然 AF2 竞争 ABS 位点，从而阻断 AF2 与 ERRγ LBD 结构域结合的活性状态。自抑制肽源自覆盖 SBP 的 AF2 区域，我们预计它可以通过减少其内在无序和重新结合时的熵成本，有效地重新结合到 ABS 位点。为此，采用了烃装订，即在自抑制肽的 N 端、中间或 C 端区域中的 [i，i  4]-锚定残基对上采用全烃桥。正如所料，钉合肽是 ERRγ LBD 结构域的良好结合者，可以有效与天然 AF2 螺旋尾竞争 ERRγ ABS 位点，与 AF2 对该位点表现出基本相似的结合模式，并形成多样化的非共价键与位点相互作用，从而赋予结构域-肽复合物稳定性和特异性。© 2024 Wiley periodicals LLC。

Orphan nuclear estrogen-related receptor γ (ERRγ) has been recognized as a potential therapeutic target for cancer, inflammation and metabolic disorder. The ERRγ contains a regulatory AF2 helical tail linked C-terminally to its ligand-binding domain (LBD), which is a self-binding peptide (SBP) and serves as molecular switch to dynamically regulate the receptor alternation between active and inactive states by binding to and unbinding from the AF2-binding site on ERRγ LBD surface, respectively. Traditional ERRγ modulators are all small-molecule chemical ligands that can be classified into agonists and inverse agonists in terms of their action mechanism; the agonists stabilize the AF2 in ABS site with an agonist conformation, while the inverse agonists lock the AF2 out of the site to largely abolish ERRγ transcriptional activity. Here, a class of ERRγ peptidic antagonists was described to compete with native AF2 for the ABS site, thus blocking the active state of AF2 binding to ERRγ LBD domain. Self-inhibitory peptide was derived from the SBP-covering AF2 region and we expected it can rebind potently to the ABS site by reducing its intrinsic disorder and entropy cost upon the rebinding. Hydrocarbon stapling was employed to do so, which employed an all-hydrocarbon bridge across the [i, i + 4]-anchor residue pair in the N-terminal, middle or C-terminal region of the self-inhibitory peptide. As might be expected, it is revealed that the stapled peptides are good binders of ERRγ LBD domain and can effectively compete with the native AF2 helical tail for ERRγ ABS site, which exhibit a basically similar binding mode with AF2 to the site and form diverse noncovalent interactions with the site, thus conferring stability and specificity to the domain-peptide complexes.© 2024 Wiley Periodicals LLC.