Structural insight into the activation of a class B G-protein-coupled receptor by peptide hormones in live human cells
Structural insight into the activation of a class B G-protein-coupled receptor by peptide hormones in live human cells
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DOI：
10.7554/elife.27711
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发表时间：
2017-08
期刊：
影响因子：
7.7
通讯作者：
L. Seidel;B. Zarzycka;S. Zaidi;V. Katritch;Irene Coin
中科院分区：
文献类型：
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作者：
L. Seidel;B. Zarzycka;S. Zaidi;V. Katritch;Irene Coin
B类G蛋白偶联受体（GPCR）的激活机制在很大程度上仍然未知。为了表征肽类激素诱导的构象变化，我们研究了B类促肾上腺皮质激素释放因子受体1型（CRF 1 R）与两种肽激动剂和三种肽拮抗剂的相互作用，所述肽拮抗剂通过N-截短的激动剂获得。用遗传编码的光交联剂和成对交联的表面作图揭示了CRF 1 R跨膜结构域（TMD）上激动剂和拮抗剂的不同足迹，并直接从活的人细胞中的完整受体中鉴定了许多配体-受体接触位点。这些数据使得能够生成CRF-和CRF（12-41）-结合的CRF 1 R的原子模型，通过分子动力学模拟进一步探索。我们发现，结合激动剂和拮抗剂采用不同的折叠和稳定不同的TMD构象，这涉及弯曲的螺旋VI和VII周围灵活的甘氨酸铰链。这些甘氨酸铰链在所有B类GPCR中的保守性表明它们在这些受体的活化中的一般作用。DOI：http://dx.doi.org/10.7554/eLife.27711.001网站
The activation mechanism of class B G-protein-coupled receptors (GPCRs) remains largely unknown. To characterize conformational changes induced by peptide hormones, we investigated interactions of the class B corticotropin-releasing factor receptor type 1 (CRF1R) with two peptide agonists and three peptide antagonists obtained by N-truncation of the agonists. Surface mapping with genetically encoded photo-crosslinkers and pair-wise crosslinking revealed distinct footprints of agonists and antagonists on the transmembrane domain (TMD) of CRF1R and identified numerous ligand-receptor contact sites, directly from the intact receptor in live human cells. The data enabled generating atomistic models of CRF- and CRF(12-41)-bound CRF1R, further explored by molecular dynamics simulations. We show that bound agonist and antagonist adopt different folds and stabilize distinct TMD conformations, which involves bending of helices VI and VII around flexible glycine hinges. Conservation of these glycine hinges among all class B GPCRs suggests their general role in activation of these receptors. DOI: http://dx.doi.org/10.7554/eLife.27711.001