Sandbox Reserved 642: Difference between revisions

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'''Catalytic Domain'''
'''Catalytic Domain'''
The <scene name='Sandbox_Reserved_642/Catalytic_domain/1'>catalytic domain</scene> of phenylalanine hydroxylase includes resides 143-410.  This region has a basket-like arrangement consisting of 13 alpha-helices and 8 beta-strands. This region of the protein also includes the active site.  The active site of PheOH can be found in the center of the catalytic domain and is characterized by a 13 Angstroms deep and 10 Angstroms wide hydrophobic pocket. Lining the active site are 3 glutamates, 2 histadines and 1 tyrosine residue along with hydrophobic residues for a total of 34 amino acids. Covering the entrance of the active site is a short loop consisting or residues 378-381.   
The <scene name='Sandbox_Reserved_642/Catalytic_domain/1'>catalytic domain</scene> of phenylalanine hydroxylase includes resides 143-410.  This region has a basket-like arrangement consisting of 13 alpha-helices and 8 beta-strands. This region of the protein also includes the active site.  The active site of PheOH can be found in the center of the catalytic domain and is characterized by a 13 Angstroms deep and 10 Angstroms wide hydrophobic pocket. Lining the active site are 3 glutamates, 2 histadines and 1 tyrosine residue along with hydrophobic residues for a total of 34 amino acids. Covering the entrance of the active site is a short loop consisting or residues 378-381.   
The center of each catalytic domain consists of an iron ion which is vital to the enzyme activity.  The iron atom binds in the active site to  <scene name='Sandbox_Reserved_642/Iron_binding/2'>histadine residues 285 and 290, 1 oxygen atom in glutamate 330</scene>. Histadine 285 and 290 were found to be required for the binding of iron through site directed mutagenisis studies.  The iron ions are coordinated to three water molecules and arrange in an octahedral geometry.  The active site also binds the cofactor tetrahydrobiopterin.  This cofactor binds closely to the iron ion and forma hydrogen bonds with two of the three water molecules.  The cofactor also forms hydrogen bonds with the carbonyl oxygen of the protein residues including Ala322, Gly247, and Leu249 and the amide of Leu249.<ref> Erlandsen H., DirSci; Marianne G. Patch, PhD; Alejandra Gamez, PhD; Mary Straub; and Raymond C. Stevens, PhD. Structural Studies on Phenylalanine Hydroxylase and Implications Toward Understanding and Treating Phenylketonuria [http://www.pkuworld.org/home/docs/literature/erlandsen_2003_p.pdf]</ref>
The center of each catalytic domain consists of an iron ion which is vital to the enzyme activity.  The iron atom binds in the active site to  <scene name='Sandbox_Reserved_642/Iron_binding/2'>histadine residues 285 and 290, 1 oxygen atom in glutamate 330</scene>. Histadine 285 and 290 were found to be required for the binding of iron through site directed mutagenisis studies.  The iron ions are coordinated to three water molecules and arrange in an octahedral geometry.  The active site also binds the  
<scene name='Sandbox_Reserved_642/Cofactor/1'>cofactor tetrahydrobiopterin</scene>.  This cofactor binds closely to the iron ion and forma hydrogen bonds with two of the three water molecules.  The cofactor also forms hydrogen bonds with the carbonyl oxygen of the protein residues including Ala322, Gly247, and Leu249 and the amide of Leu249.<ref> Erlandsen H., DirSci; Marianne G. Patch, PhD; Alejandra Gamez, PhD; Mary Straub; and Raymond C. Stevens, PhD. Structural Studies on Phenylalanine Hydroxylase and Implications Toward Understanding and Treating Phenylketonuria [http://www.pkuworld.org/home/docs/literature/erlandsen_2003_p.pdf]</ref>


'''Tetramerization Domain'''  
'''Tetramerization Domain'''  
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'''Regulatory Domain'''
'''Regulatory Domain'''
Housed in the N-terminus, the regulatory domain contains residues 19-142 and is more flexible than the other domains. The core of this domain contains an alpha beta sandwich and a beta alpha beta double motif. <ref> Bostjan Kobe, Ian G. Jennings, Colin M. House1, Belinda J. Michell, Kenneth E. Goodwill, Bernard D. Santarsiero, Raymond C. Stevens, Richard G. H. Cotton and Bruce E. Kemp. Nature Structural Biology  6, 442 - 448 (1999), Structural basis of autoregulation of phenylalanine hydroxylase, [http://http://www.nature.com/nsmb/journal/v6/n5/full/nsb0599_442.html]</ref>
Housed in the N-terminus, the regulatory domain contains residues 19-142 and is more flexible than the other domains. The core of this domain contains an alpha beta sandwich and a beta alpha beta double motif. <ref> Bostjan Kobe, Ian G. Jennings, Colin M. House1, Belinda J. Michell, Kenneth E. Goodwill, Bernard D. Santarsiero, Raymond C. Stevens, Richard G. H. Cotton and Bruce E. Kemp. Nature Structural Biology  6, 442 - 448 (1999), Structural basis of autoregulation of phenylalanine hydroxylase, [http://http://www.nature.com/nsmb/journal/v6/n5/full/nsb0599_442.html]</ref>


== '''Mechanism''' ==
== '''Mechanism''' ==