Sandbox Reserved 480: Difference between revisions

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== Structure ==

[[Image:Tetrameric_2pah_mm1.png | thumb | Tetrameric Structure of PheOH]]

These hydroxylases are tetramers which contain homologous subunits. In this scene it can be viewed as a <scene name='Sandbox_Reserved_480/Dimer/1'>dimer</scene>. Each subunit is made up of three domains: the regulatory domain, catalytic domain, and tetramerization domain. The regulatory domain is in the N-terminus region of the chain. The catalytic domain is found in the middle nearing the C-terminus and the last set of residues make up the tetramerization domain, which helps form the tetrameric structure. The regulatory domain affects the function of the active site. When the regulatory domain is <scene name='Sandbox_Reserved_480/Phosphorylated_pheoh/2'>phosphorylated</scene>, the active site is closed off and prevented form interacting with the substrates. In this scene the chain is colored from N-terminus to C-terminus blue to red and the active site and Fe (III) is colored black. In the <scene name='Sandbox_Reserved_480/Dephosphorylated_pheoh/1'>dephosphorylated</scene> PheOH, the active site is open to the subtrates and can convert them to products. Each subunit’s <scene name='Sandbox_Reserved_480/Active_site/4'>catalytic</scene> site is identified by an iron atom residing at the bottom of 10 Å deep cleft in the enzyme surface.<ref name="BH4_H"/> Fe is bound to three amino acid residues; His285, His290, and Glu184. Throughout the entire process of catalysis the Fe atom is in its ferrous form.

These structures have been identified using x-ray diffraction chrystallography. These hydroxylases are tetramers which contain homologous subunits. In this scene it can be viewed as a <scene name='Sandbox_Reserved_480/Dimer/1'>dimer</scene>. Each subunit is made up of three domains: the regulatory domain, catalytic domain, and tetramerization domain. The regulatory domain is in the N-terminus region of the chain. The catalytic domain is found in the middle nearing the C-terminus and the last set of residues make up the tetramerization domain, which helps form the tetrameric structure. The regulatory domain affects the function of the active site. When the regulatory domain is <scene name='Sandbox_Reserved_480/Phosphorylated_pheoh/2'>phosphorylated</scene>, the active site is closed off and prevented form interacting with the substrates. In this scene the chain is colored from N-terminus to C-terminus blue to red and the active site and Fe (III) is colored black. In the <scene name='Sandbox_Reserved_480/Dephosphorylated_pheoh/1'>dephosphorylated</scene> PheOH, the active site is open to the subtrates and can convert them to products. Each subunit’s <scene name='Sandbox_Reserved_480/Active_site/4'>catalytic</scene> site is identified by an iron atom residing at the bottom of 10 Å deep cleft in the enzyme surface.<ref name="BH4_H"/> Fe is bound to three amino acid residues; His285, His290, and Glu184. Throughout the entire process of catalysis the Fe atom is in its ferrous form.

This enzyme contains both hydrophobic and hydrophilic <scene name='Sandbox_Reserved_480/Hydrophobic_residues/1'>residues</scene>. Alpha-helices, loops, and beta-sheets can be found in each of the subuntis, though the helices are the more prominent <scene name='Sandbox_Reserved_480/Secondary_structures/1'>secondary</scene> structure.

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[[Image:Domain phenylketonuria 4.jpg | 500px]]

== Mechanism ==

Catalysis does not begin until all three substrates, oxygen, phenylalanine, and tetrahydrobiopterin, are bound to the enzyme. There are some inconsistencies with what order the substrates bind, but some studies suggest that the oxygen binds first and the order of Phe and tetrahydrobiopterin is interchangeable.

Catalysis does not begin until all three substrates, oxygen, phenylalanine, and tetrahydrobiopterin, are bound to the enzyme. There are some inconsistencies with what order the substrates bind, but some studies suggest that the oxygen binds first and the order of Phe and tetrahydrobiopterin is interchangeable. The Glu residue of the active site is important in that it is the only direct connection between the the enzyme and the tetrahydrobiopterin. The substrates Phe and tetrahydrobiopterin get oxidized in this reaction, a hydroxyl group is added to the side chain. The products of the reaction include tyrosine and quinonoid dihyrdrobiopterin.

[[Image:Phe_reaction_1.png | Phenylalanine mechanism]]

Sandbox Reserved 480: Difference between revisions

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@@ Line 11: / Line 11: @@
 == Structure ==
 [[Image:Tetrameric_2pah_mm1.png | thumb | Tetrameric Structure of PheOH]]
-These hydroxylases are tetramers which contain homologous subunits. In this scene it can be viewed as a <scene name='Sandbox_Reserved_480/Dimer/1'>dimer</scene>. Each subunit is made up of three domains: the regulatory domain, catalytic domain, and tetramerization domain. The regulatory domain is in the N-terminus region of the chain. The catalytic domain is found in the middle nearing the C-terminus and the last set of residues make up the tetramerization domain, which helps form the tetrameric structure. The regulatory domain affects the function of the active site. When the regulatory domain is <scene name='Sandbox_Reserved_480/Phosphorylated_pheoh/2'>phosphorylated</scene>, the active site is closed off and prevented form interacting with the substrates. In this scene the chain is colored from N-terminus to C-terminus blue to red and the active site and Fe (III) is colored black. In the <scene name='Sandbox_Reserved_480/Dephosphorylated_pheoh/1'>dephosphorylated</scene> PheOH, the active site is open to the subtrates and can convert them to products. Each subunit’s <scene name='Sandbox_Reserved_480/Active_site/4'>catalytic</scene> site is identified by an iron atom residing at the bottom of 10 Å deep cleft in the enzyme surface.<ref name="BH4_H"/> Fe is bound to three amino acid residues; His285, His290, and Glu184. Throughout the entire process of catalysis the Fe atom is in its ferrous form.
+These structures have been identified using x-ray diffraction chrystallography. These hydroxylases are tetramers which contain homologous subunits. In this scene it can be viewed as a <scene name='Sandbox_Reserved_480/Dimer/1'>dimer</scene>. Each subunit is made up of three domains: the regulatory domain, catalytic domain, and tetramerization domain. The regulatory domain is in the N-terminus region of the chain. The catalytic domain is found in the middle nearing the C-terminus and the last set of residues make up the tetramerization domain, which helps form the tetrameric structure. The regulatory domain affects the function of the active site. When the regulatory domain is <scene name='Sandbox_Reserved_480/Phosphorylated_pheoh/2'>phosphorylated</scene>, the active site is closed off and prevented form interacting with the substrates. In this scene the chain is colored from N-terminus to C-terminus blue to red and the active site and Fe (III) is colored black. In the <scene name='Sandbox_Reserved_480/Dephosphorylated_pheoh/1'>dephosphorylated</scene> PheOH, the active site is open to the subtrates and can convert them to products. Each subunit’s <scene name='Sandbox_Reserved_480/Active_site/4'>catalytic</scene> site is identified by an iron atom residing at the bottom of 10 Å deep cleft in the enzyme surface.<ref name="BH4_H"/> Fe is bound to three amino acid residues; His285, His290, and Glu184. Throughout the entire process of catalysis the Fe atom is in its ferrous form.
 This enzyme contains both <font color='#696969'>hydrophobic</font> and <font color='#8A2BE2'>hydrophilic</font> <scene name='Sandbox_Reserved_480/Hydrophobic_residues/1'>residues</scene>. <font color='hotpink'>Alpha-helices</font>, loops, and <font color='yellow'>beta-sheets</font> can be found in each of the subuntis, though the helices are the more prominent <scene name='Sandbox_Reserved_480/Secondary_structures/1'>secondary</scene> structure.
@@ Line 22: / Line 22: @@
 [[Image:Domain phenylketonuria 4.jpg | 500px]]
 == Mechanism ==
-Catalysis does not begin until all three substrates, oxygen, phenylalanine, and tetrahydrobiopterin, are bound to the enzyme. There are some inconsistencies with what order the substrates bind, but some studies suggest that the oxygen binds first and the order of Phe and tetrahydrobiopterin is interchangeable.
+Catalysis does not begin until all three substrates, oxygen, phenylalanine, and tetrahydrobiopterin, are bound to the enzyme. There are some inconsistencies with what order the substrates bind, but some studies suggest that the oxygen binds first and the order of Phe and tetrahydrobiopterin is interchangeable. The Glu residue of the active site is important in that it is the only direct connection between the the enzyme and the tetrahydrobiopterin. The substrates Phe and tetrahydrobiopterin get oxidized in this reaction, a hydroxyl group is added to the side chain. The products of the reaction include tyrosine and quinonoid dihyrdrobiopterin.
 [[Image:Phe_reaction_1.png | Phenylalanine mechanism]]