Sandbox Reserved 773: Difference between revisions

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[[Image:Histidine Decarboxylase Binding Site.png|thumb|right|Figure 3. Interactions between enzyme HDC and cofactor-substrate PLP-HME at the binding site <ref name=jbc/>.]]

The ~~binding pocket~~ for the cofactor PLP and the substrate histidine is located at the large domain. Since Histidine methyl ester (HME) is a substrate analog, PLP-HME can be utilized to demonstrate the binding interaction for the substrate-enzyme transition state at the active site <ref name=jbc/> <ref name=inhibition>PMID:850236</ref>. A one-dimensional representation of PLP-HME residing in the binding pocket can be seen in Figure 3. The hydrophobic pocket of the active site are produced by several hydrophobic amino acids including Trp-72, Tyr-80, Leu-102, Phe-104, Ala-275, Tyr-334, Ile-436 (Figure 3). This hydrophobic pocket allow for the substrate to be protected from the solvent during the catalytic reaction.

The <scene name='56/564049/Binding/1'>Catalytic site</scene> for the cofactor PLP and the substrate histidine is located at the large domain. Since Histidine methyl ester (HME) is a substrate analog, PLP-HME can be utilized to demonstrate the binding interaction for the substrate-enzyme transition state at the active site <ref name=jbc/> <ref name=inhibition>PMID:850236</ref>. A one-dimensional representation of PLP-HME residing in the binding pocket can be seen in Figure 3. The hydrophobic pocket of the active site are produced by several hydrophobic amino acids including Trp-72, Tyr-80, Leu-102, Phe-104, Ala-275, Tyr-334, Ile-436 (Figure 3). This hydrophobic pocket allow for the substrate to be protected from the solvent during the catalytic reaction.

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A loop region appears between the residues 330 to 340 of the large domain <ref name=jbc/>. This loop protrudes from the large domain into the active site of another subunit of the dimer and makes up the entrance of the active site. Especially Tyr-334, which directly interacts with the backbone of Ser-195 through a fairly weak hydrogen bond <ref name=jbc/>. Due to the weak hydrogen bonding, the loop’s position is not rigidly fixed. Thus, this causes this loop to be fairly flexible enabling it to act as a gate to “open” or “close” the active site <ref name=jbc/>.

== Enzymatic Mechanism ==

Sandbox Reserved 773: Difference between revisions

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@@ Line 57: / Line 57: @@
 [[Image:Histidine Decarboxylase Binding Site.png|thumb|right|Figure 3. Interactions between enzyme HDC and cofactor-substrate PLP-HME at the binding site <ref name=jbc/>.]]
-The binding pocket for the cofactor PLP and the substrate histidine is located at the large domain. Since Histidine methyl ester (HME) is a substrate analog, PLP-HME can be utilized to demonstrate the binding interaction for the substrate-enzyme transition state at the active site <ref name=jbc/> <ref name=inhibition>PMID:850236</ref>. A one-dimensional representation of PLP-HME residing in the binding pocket can be seen in Figure 3. The hydrophobic pocket of the active site are produced by several hydrophobic amino acids including Trp-72, Tyr-80, Leu-102, Phe-104, Ala-275, Tyr-334, Ile-436 (Figure 3). This hydrophobic pocket allow for the substrate to be protected from the solvent during the catalytic reaction.
+The <scene name='56/564049/Binding/1'>Catalytic site</scene> for the cofactor PLP and the substrate histidine is located at the large domain. Since Histidine methyl ester (HME) is a substrate analog, PLP-HME can be utilized to demonstrate the binding interaction for the substrate-enzyme transition state at the active site <ref name=jbc/> <ref name=inhibition>PMID:850236</ref>. A one-dimensional representation of PLP-HME residing in the binding pocket can be seen in Figure 3. The hydrophobic pocket of the active site are produced by several hydrophobic amino acids including Trp-72, Tyr-80, Leu-102, Phe-104, Ala-275, Tyr-334, Ile-436 (Figure 3). This hydrophobic pocket allow for the substrate to be protected from the solvent during the catalytic reaction.
@@ Line 64: / Line 64: @@
 A loop region appears between the residues 330 to 340 of the large domain <ref name=jbc/>. This loop protrudes from the large domain into the active site of another subunit of the dimer and makes up the entrance of the active site. Especially Tyr-334, which directly interacts with the backbone of Ser-195 through a fairly weak hydrogen bond <ref name=jbc/>. Due to the weak hydrogen bonding, the loop’s position is not rigidly fixed. Thus, this causes this loop to be fairly flexible enabling it to act as a gate to “open” or “close” the active site <ref name=jbc/>.
 == Enzymatic Mechanism ==