G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors. Class B1 GPCRs constitute a subfamily of 15 receptors that characteristically contain large extracellular domains (ECDs) and respond to long polypeptide hormones. Class B1 GPCRs are critical regulators of homeostasis, and, as such, many are important drug targets. While most transmembrane proteins, including GPCRs, are recalcitrant to crystallization, recent advances in cryo-electron microscopy (cryo-EM) have facilitated a rapid expansion of the structural understanding of membrane proteins. As a testament to this success, structures for all the class B1 receptors bound to G proteins have been determined by cryo-EM in the past 5 years. Further advances in cryo-EM have uncovered dynamics of these receptors, ligands, and signaling partners. Here, we examine the recent structural underpinnings of the class B1 GPCRs with an emphasis on structure-function relationships.

中文翻译：

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对 B1 类 GPCR 的结构和功能的新见解。

G 蛋白偶联受体 (GPCR) 是最大的细胞表面受体家族。B1 类 GPCR 构成 15 个受体的亚家族，这些受体的特征是包含大的细胞外结构域 (ECD) 并对长多肽激素作出反应。B1 类 GPCR 是体​​内平衡的关键调节剂，因此，许多是重要的药物靶点。虽然包括 GPCR 在内的大多数跨膜蛋白都难以结晶，但冷冻电子显微镜 (cryo-EM) 的最新进展促进了对膜蛋白结构理解的快速扩展。作为这一成功的证明，在过去 5 年中，冷冻电子显微镜已经确定了与 G 蛋白结合的所有 B1 类受体的结构。cryo-EM 的进一步发展揭示了这些受体、配体和信号伙伴的动态。这里，