Sandbox Reserved 1473: Difference between revisions

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'''ENERGETICS'''

[[Image:Energetics1.png|thumb|upright=1.5| Salt bridge formation]]

[[Image:Energetics2.png|thumb|upright=1.5|Hydrogen bond formation]]

Experimental studies have shown that GPCRs do trigger cellular activities in their unbound states at a minimum basal levels. Studies have also shown that even when bound to agonists, GPCRs express characteristics that range from inactive to a continuum of partially active structures in the absence of the G protein. This means that the presence of the agonist plays an important role in the activation of GPCRs.

The kind and specificity of the agonists determine the activation pathway taken by GPCRs in terms of the energy ordering of the different states which is also premeditated by the respective activation energy landscapes. This means that the agonist-bound inactive state will have the lowest energy state among the various states within the degree of activation.

The stabilizing factor of the activated state of the GPCRs is attributed to the interactions between the Ga (G alpha subunit) and the GPCR.

Activation of the G-protein can be explained by interactions between the GPCR (specifically the ICD) and the G-alpha subunit. During analysis, Molecular Dynamics (MD) simulations found that there is formation of Salt-bridges and Hydrogen bonds between the C-terminal helix of G∝i and some regions in the ICD. Salt-bridges form between D261, D350 of G∝i and K72 of the IC loop 1 and R51 of IC loop 2. There's also formation of Hydrogen bonds between C351 and R137 of the G∝i that replace the inactive state R151-D136-R137-T247 network.Another salt-bridge is formed between the carboxylate group on the G∝i C-terminal residue F354 and K245 of the TM6 and R239 of the IC loop 3. All these structural changes facilitate ligand binding to receptor with high affinity and specificity and leads to an ordered state that further accommodates a more tighter binding to the ligand. The ICD then release the D/E R Y sequence motif from the TMD and this process is coupled to the binding of a ligand that is specific to the coupled domain (G-protein).Full activation occurs when G-proteins bind to the ICD. The stabilizing factor of the activated state of the GPCRs is attributed to the interactions between the Ga (G alpha subunit) and the GPCR.

Sandbox Reserved 1473: Difference between revisions

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@@ Line 70: / Line 70: @@
 '''ENERGETICS'''
+[[Image:Energetics1.png|thumb|upright=1.5| Salt bridge formation]]
+[[Image:Energetics2.png|thumb|upright=1.5|Hydrogen bond formation]]
 Experimental studies have shown that GPCRs do trigger cellular activities in their unbound states at a minimum basal levels. Studies have also shown that even when bound to agonists, GPCRs express characteristics that range from inactive to a continuum of partially active structures in the absence of the G protein. This means that the presence of the agonist plays an important role in the activation of GPCRs.
 The kind and specificity of the agonists determine the activation pathway taken by GPCRs in terms of the energy ordering of the different states which is also premeditated by the respective activation energy landscapes. This means that the agonist-bound inactive state will have the lowest energy state among the various states within the degree of activation.
-The stabilizing factor of the activated state of the GPCRs is attributed to the interactions between the Ga (G alpha subunit) and the GPCR.
+Activation of the G-protein can be explained by interactions between the GPCR (specifically the ICD) and the G-alpha subunit. During analysis, Molecular Dynamics (MD) simulations found that there is formation of Salt-bridges and Hydrogen bonds between the C-terminal helix of G∝i and some regions in the ICD. Salt-bridges form between D261, D350 of G∝i and K72 of the IC loop 1 and R51 of IC loop 2. There's also  formation of Hydrogen bonds between C351 and R137 of the G∝i that replace the inactive state R151-D136-R137-T247 network.Another salt-bridge is formed between the carboxylate group on the G∝i C-terminal residue F354 and K245 of the TM6 and R239 of the IC loop 3. All these structural changes facilitate ligand binding to receptor with high affinity and specificity and leads to an ordered state that further accommodates a more tighter binding to the ligand. The ICD then release the D/E R Y sequence motif from the TMD and this process is coupled to the binding of a ligand that is specific to the coupled domain (G-protein).Full activation occurs when G-proteins bind to the ICD. The stabilizing factor of the activated state of the GPCRs is attributed to the interactions between the Ga (G alpha subunit) and the GPCR.