ABCC8 p.Tyr179Trp
Predicted by SNAP2: | A: D (59%), C: D (63%), D: D (59%), E: D (75%), F: D (66%), G: N (53%), H: D (63%), I: D (71%), K: D (71%), L: D (71%), M: D (71%), N: N (61%), P: D (75%), Q: D (63%), R: D (80%), S: N (53%), T: D (59%), V: D (66%), W: D (75%), |
Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: N, G: D, H: N, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, |
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[hide] Structural model of ligand-G protein-coupled recep... J Biol Chem. 2011 Sep 9;286(36):31661-75. Epub 2011 Jun 17. Marquer C, Fruchart-Gaillard C, Letellier G, Marcon E, Mourier G, Zinn-Justin S, Menez A, Servent D, Gilquin B
Structural model of ligand-G protein-coupled receptor (GPCR) complex based on experimental double mutant cycle data: MT7 snake toxin bound to dimeric hM1 muscarinic receptor.
J Biol Chem. 2011 Sep 9;286(36):31661-75. Epub 2011 Jun 17., [PMID:21685390]
Abstract [show]
The snake toxin MT7 is a potent and specific allosteric modulator of the human M1 muscarinic receptor (hM1). We previously characterized by mutagenesis experiments the functional determinants of the MT7-hM1 receptor interaction (Fruchart-Gaillard, C., Mourier, G., Marquer, C., Stura, E., Birdsall, N. J., and Servent, D. (2008) Mol. Pharmacol. 74, 1554-1563) and more recently collected evidence indicating that MT7 may bind to a dimeric form of hM1 (Marquer, C., Fruchart-Gaillard, C., Mourier, G., Grandjean, O., Girard, E., le Maire, M., Brown, S., and Servent, D. (2010) Biol. Cell 102, 409-420). To structurally characterize the MT7-hM1 complex, we adopted a strategy combining double mutant cycle experiments and molecular modeling calculations. First, thirty-three ligand-receptor proximities were identified from the analysis of sixty-one double mutant binding affinities. Several toxin residues that are more than 25 A apart still contact the same residues on the receptor. As a consequence, attempts to satisfy all the restraints by docking the toxin onto a single receptor failed. The toxin was then positioned onto two receptors during five independent flexible docking simulations. The different possible ligand and receptor extracellular loop conformations were described by performing simulations in explicit solvent. All the docking calculations converged to the same conformation of the MT7-hM1 dimer complex, satisfying the experimental restraints and in which (i) the toxin interacts with the extracellular side of the receptor, (ii) the tips of MT7 loops II and III contact one hM1 protomer, whereas the tip of loop I binds to the other protomer, and (iii) the hM1 dimeric interface involves the transmembrane helices TM6 and TM7. These results structurally support the high affinity and selectivity of the MT7-hM1 interaction and highlight the atypical mode of interaction of this allosteric ligand on its G protein-coupled receptor target.
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No. Sentence Comment
271 This distance is similar to the distance between the two MT7 binding sites centered on Tyr-179/Trp-400 of each protomer in our model of MT7-hM1 dimer complex (Fig. 8B).
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ABCC8 p.Tyr179Trp 21685390:271:87
status: NEW277 In this case, the distance between the two MT7 binding sites (Tyr-179/Trp-400) is too large (35 Å) to receive the tips of MT7 loops (Fig. 8C).
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ABCC8 p.Tyr179Trp 21685390:277:62
status: NEW280 Fig. 8D shows the variation of the distances between the MT7 binding sites (Tyr-179/Trp-400) of both protomers as a function of the angle of rotation of each protomer around their vertical axis.
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ABCC8 p.Tyr179Trp 21685390:280:76
status: NEW283 This is due to the fact that Tyr-179/Trp- FIGURE 5.
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ABCC8 p.Tyr179Trp 21685390:283:29
status: NEW336 Therefore, the MT7-hM1 dimer recognition site is composed of three patches on MT7 (the tips of the three loops) and two patches on the hM1 side (the binding sites of the two protomers; Tyr-179/Trp-400), forming a totalinterfaceareaequalto2400Å2 .Thisvalueisclosetothemean valueoftheprotein/proteininterfaceareasreportedfortwo-patch interactions (2500 Å2 ) (73).
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ABCC8 p.Tyr179Trp 21685390:336:185
status: NEW350 B, hM1 dimer conformation calculated from our experimental data viewed from the extracellular face (Tyr-179/Trp-400 in green).
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ABCC8 p.Tyr179Trp 21685390:350:100
status: NEW351 C, hM1 dimer conformation based on the CXCR4 chemokine structure viewed from the extracellular face (Tyr-179/Trp-400 in yellow).
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ABCC8 p.Tyr179Trp 21685390:351:101
status: NEW352 D, measurements of the distancesbetweenthetwocentersofgravityoftheprotomersofthereceptor (E) and the two centers of mass of the MT7 binding sites (Tyr-179/Trp-400) of the protomers (f) during the step by step rotation of each protomer around their vertical axis.
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ABCC8 p.Tyr179Trp 21685390:352:147
status: NEW