Sandbox Reserved 1722: Difference between revisions

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==== ''DRY Motif'' ====

The DRY motif is a proton microswitch that is located near the G-protein binding site C-terminal on TM3 <ref name="Schonegge"/>. It acts as lock when the GPCR is not being activated, preventing unnecessary activation of the G-proteins <ref name="Zhou"/>. This motif is conserved in typical Class A GPCRS however, in MRGPRX2 it is only partially conserved. The arginine is conserved, while the aspartate is replaced by a glutamate and the tyrosine is replaced by a cysteine <ref name="Yang"/> <ref name="Sandoval">Sandoval, A., et al. "The Molecular Switching Mechanism at the Conserved D(E)RY Motif in Class-A GPCRs." Biophysical journal, 111(1), 79-89. https://doi.org/10.1016/j.bpj.2016.06.004 </ref> (Figure 2). The replacement of tyrosine for cysteine results in the helices coming closer together, creating a shallower binding pocket<ref name="Zhou"/>.

The DRY motif is a proton microswitch that is located near the G-protein binding site C-terminal on TM3 <ref name="Schonegge"/>. It acts as lock when the GPCR is not being activated, preventing unnecessary activation of the G-proteins <ref name="Zhou"/>. This motif is conserved in typical Class A GPCRS however, in MRGPRX2 it is only partially conserved. The arginine is conserved, while the aspartate is replaced by a glutamate and the tyrosine is replaced by a cysteine <ref name="Yang"/> <ref name="Sandoval">Sandoval, A., et al. "The Molecular Switching Mechanism at the Conserved D(E)RY Motif in Class-A GPCRs." Biophysical journal, 111(1), 79-89. https://doi.org/10.1016/j.bpj.2016.06.004 </ref> (Figure 2). The replacement of tyrosine for cysteine results in the helices coming closer together, creating a shallower binding pocket <ref name="Zhou"/>.

==== ''Sodium Binding'' ====

The sodium site motif facilitates the conformational change of GPCR upon activation<ref name="Katritch">PMID: 24767681</ref>. A sodium molecule sits in the middle of the TM7 helices where it is stabilized by conserved residues aspartate (TM2), serine (TM2), and three water molecules. The sodium is able to make a salt bridge with the aspartate at this position. The sodium acts similar to a ball joint in which it allows for the TM helices be spread apart and induce larger conformational change upon binding. In MRGPRX2, this motif is only partially conserved. The aspartate (TM2) is conserved while the serine is replaced by a glycine <ref name="Yang"/> .This creates a less favorable environment for the stabilization of sodium due to serine being polar while glycine is nonpolar. Currently, in crystallization structures no sodium has been seen at this site. Thus making it inconclusive on whether it plays a role in the conformational change to activate G-proteins upon binding to the receptor <ref name="Yang"/> .

The sodium site motif facilitates the conformational change of GPCR upon activation <ref name="Katritch">PMID: 24767681</ref>. A sodium molecule sits in the middle of the TM7 helices where it is stabilized by conserved residues aspartate (TM2), serine (TM2), and three water molecules. The sodium is able to make a salt bridge with the aspartate at this position. The sodium acts similar to a ball joint in which it allows for the TM helices be spread apart and induce larger conformational change upon binding. In MRGPRX2, this motif is only partially conserved. The aspartate (TM2) is conserved while the serine is replaced by a glycine <ref name="Yang"/>. This creates a less favorable environment for the stabilization of sodium due to serine being polar while glycine is nonpolar. Currently, in crystallization structures no sodium has been seen at this site. Thus making it inconclusive on whether it plays a role in the conformational change to activate G-proteins upon binding to the receptor <ref name="Yang"/>.

== MRGPRX2 Signaling Pathway ==

Sandbox Reserved 1722: Difference between revisions

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@@ Line 38: / Line 38: @@
 ==== ''DRY Motif'' ====
-The DRY motif is a proton microswitch that is located near the G-protein binding site C-terminal on TM3 <ref name="Schonegge"/>.  It acts as lock when the GPCR is not being activated, preventing unnecessary activation of the G-proteins <ref name="Zhou"/>. This motif is conserved in typical Class A GPCRS however, in MRGPRX2 it is only partially conserved. The arginine is conserved, while the aspartate is replaced by a glutamate and the tyrosine is replaced by a cysteine <ref name="Yang"/> <ref name="Sandoval">Sandoval, A., et al. "The Molecular Switching Mechanism at the Conserved D(E)RY Motif in Class-A GPCRs." Biophysical journal, 111(1), 79-89. https://doi.org/10.1016/j.bpj.2016.06.004 </ref> (Figure 2). The replacement of tyrosine for cysteine results in the helices coming closer together, creating a shallower binding pocket<ref name="Zhou"/>.
+The DRY motif is a proton microswitch that is located near the G-protein binding site C-terminal on TM3 <ref name="Schonegge"/>.  It acts as lock when the GPCR is not being activated, preventing unnecessary activation of the G-proteins <ref name="Zhou"/>. This motif is conserved in typical Class A GPCRS however, in MRGPRX2 it is only partially conserved. The arginine is conserved, while the aspartate is replaced by a glutamate and the tyrosine is replaced by a cysteine <ref name="Yang"/> <ref name="Sandoval">Sandoval, A., et al. "The Molecular Switching Mechanism at the Conserved D(E)RY Motif in Class-A GPCRs." Biophysical journal, 111(1), 79-89. https://doi.org/10.1016/j.bpj.2016.06.004 </ref> (Figure 2). The replacement of tyrosine for cysteine results in the helices coming closer together, creating a shallower binding pocket <ref name="Zhou"/>.
 ==== ''Sodium Binding'' ====
-The sodium site motif facilitates the conformational change of GPCR upon activation<ref name="Katritch">PMID: 24767681</ref>. A sodium molecule sits in the middle of the TM7 helices where it is stabilized by conserved residues aspartate (TM2), serine (TM2), and three water molecules. The sodium is able to make a salt bridge with the aspartate at this position. The sodium acts similar to a ball joint in which it allows for the TM helices be spread apart and induce larger conformational change upon binding. In MRGPRX2, this motif is only partially conserved. The aspartate (TM2) is conserved while the serine is replaced by a glycine <ref name="Yang"/> .This creates a less favorable environment for the stabilization of sodium due to serine being polar while glycine is nonpolar. Currently, in crystallization structures no sodium has been seen at this site. Thus making it inconclusive on whether it plays a role in the conformational change to activate G-proteins upon binding to the receptor <ref name="Yang"/> .
+The sodium site motif facilitates the conformational change of GPCR upon activation <ref name="Katritch">PMID: 24767681</ref>. A sodium molecule sits in the middle of the TM7 helices where it is stabilized by conserved residues aspartate (TM2), serine (TM2), and three water molecules. The sodium is able to make a salt bridge with the aspartate at this position. The sodium acts similar to a ball joint in which it allows for the TM helices be spread apart and induce larger conformational change upon binding. In MRGPRX2, this motif is only partially conserved. The aspartate (TM2) is conserved while the serine is replaced by a glycine <ref name="Yang"/>. This creates a less favorable environment for the stabilization of sodium due to serine being polar while glycine is nonpolar. Currently, in crystallization structures no sodium has been seen at this site. Thus making it inconclusive on whether it plays a role in the conformational change to activate G-proteins upon binding to the receptor <ref name="Yang"/>.
 == MRGPRX2 Signaling Pathway ==