View source for 9p81


==NTSR1-Gi-NTS(8-13), GTP-bound Complex in the Canonical, AHD Open State (C-Open-GTP)==
<StructureSection load='9p81' size='340' side='right'caption='[[9p81]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9p81]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9P81 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9P81 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GTP:GUANOSINE-5-TRIPHOSPHATE'>GTP</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=9p81 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9p81 OCA], [https://pdbe.org/9p81 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9p81 RCSB], [https://www.ebi.ac.uk/pdbsum/9p81 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9p81 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/GBB1_HUMAN GBB1_HUMAN] Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction.<ref>PMID:18611381</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
G-protein-coupled receptors (GPCRs) are capable of signalling through four families of G protein alpha subunits. Although hundreds of nucleotide-free GPCR-G protein complex structures have been solved, the mechanism of G protein subtype selectivity remains poorly understood, with recent studies suggesting a role for dynamic nucleotide-bound intermediate states(1,2). Here we use time-resolved cryo-electron microscopy to visualize the GTP-induced activation of Galpha(i1)betagamma and Galpha(11)betagamma heterotrimers bound to the neurotensin receptor 1 (NTSR1), which has been demonstrated to be highly promiscuous in G protein coupling and to possess unusual conformations in the nucleotide-free complex. We resolve ensembles of states along the G protein activation pathway, with differences in the structures and their relative populations between Galpha(i1) and Galpha(11). Structural analysis reveals a key role for several motifs, including intracellular loop 2 (ICL2) and ICL3, in stabilizing the observed intermediate states. Our results are supported by molecular dynamics simulations and kinetic bioluminescence resonance energy transfer experiments, which reveal that the stability of these intermediate states and the signalling of various G proteins are correlated with ICL2 and ICL3 sequences. Single-molecule fluorescence assays of GTP-induced NTSR1-G protein complex dissociation reveal that NTSR1 is liberated significantly faster from Galpha(11), consistent with the relative lack of stable Galpha(11)-GTP intermediate states compared with Galpha(i1). These findings highlight that transient intermediate-state complexes along the G protein activation pathway have an important role in G protein selection that cannot be explained by nucleotide-free states alone.

Snapshots of the dynamic basis of NTSR1 G protein subtype promiscuity.,Vo AA, Modak A, Lu S, Blanchard SC, Lambert NA, Robertson MJ Nature. 2026 Mar 11. doi: 10.1038/s41586-026-10120-7. PMID:41813894<ref>PMID:41813894</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9p81" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Robertson MJ]]