ジャーナル: Structure / 年: 2025 タイトル: Cryo-EM structure of a cell-free synthesized full-length human β1-adrenergic receptor in complex with G. 著者: Felipe Merino / Zoe Köck / Utz Ermel / Philipp Dahlhaus / Anna Grimm / Anja Seybert / Jan Kubicek / Achilleas S Frangakis / Volker Dötsch / Daniel Hilger / Frank Bernhard / 要旨: The third intracellular loop (ICL3) of the β1-adrenergic receptor (β1AR) plays a critical role in regulating G protein coupling, yet the structural basis has remained unclear due to truncations of ...The third intracellular loop (ICL3) of the β1-adrenergic receptor (β1AR) plays a critical role in regulating G protein coupling, yet the structural basis has remained unclear due to truncations of ICL3 in all available structures of the β1AR in complex with G or a G protein mimetic nanobody. To address this, we used cell-free cotranslational insertion of full-length human β1AR into nanodiscs and determined its cryo-electron microscopy (cryo-EM) structure in complex with G. In this structure, ICL3 extends transmembrane helix 5, resulting in enhanced interactions with Gα and in a slight rotation of the engaged G protein. This repositioning enables new polar interactions between Gα, ICL2 and helix 8, while ICL1 and helix 8 form additional contacts with Gβ. These structural insights, supported by mutational analysis, demonstrate that ICL3 enhances G protein activation and downstream cAMP signaling by promoting more extensive interactions between the receptor and the heterotrimeric G protein.
全体 : Complex between, human Beta-1 adrenergic receptor, Gs, and nanobody-35
全体
名称: Complex between, human Beta-1 adrenergic receptor, Gs, and nanobody-35
要素
複合体: Complex between, human Beta-1 adrenergic receptor, Gs, and nanobody-35
複合体: Heterotrimeric Gs complex
タンパク質・ペプチド: Isoform Gnas-2 of Guanine nucleotide-binding protein G(s) subunit alpha isoforms short
タンパク質・ペプチド: Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1
タンパク質・ペプチド: Guanine nucleotide-binding protein G(I)/G(S)/G(O) subunit gamma-2
複合体: Beta-1 adrenergic receptor
タンパク質・ペプチド: Beta-1 adrenergic receptor
複合体: Nanobody-35
タンパク質・ペプチド: Nanobody-35
リガンド: ISOPRENALINE
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超分子 #1: Complex between, human Beta-1 adrenergic receptor, Gs, and nanobody-35
超分子
名称: Complex between, human Beta-1 adrenergic receptor, Gs, and nanobody-35 タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#3, #5, #4 詳細: The GPCR was produced cell-free and co-translationally inserted into a lipidic nanodisc. Additional Gs and Nanobody-35 during GPCR production leads to the full assembly of the complex.
由来(天然)
生物種: Homo sapiens (ヒト)
分子量
理論値: 15 KDa
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超分子 #2: Heterotrimeric Gs complex
超分子
名称: Heterotrimeric Gs complex / タイプ: complex / ID: 2 / 親要素: 1 / 含まれる分子: #1-#3 詳細: Produced in T. ni cells for later in vitro assembly of full complex.