Sandbox Reserved 642: Difference between revisions

<Structure load='2PAH_tetramer3.pdb' size='500' frame='true' align='right' caption='This is a model of the pheylalanine hydroxylase dimer as found in humans. The green ball in within each subunit represents the iron ion in the catalytic domains.' scene='Insert optional scene name here' />  

PheOH can exist as a dimer or tetramer with identical subunits. Each subunit is organized  to have a regulatory, a catalytic and a tetramerization domain. The native form of human PheOH has an estimated secondary structure composed 48% alpha-helices, 28% extended structures, 12% beta-turns, and 12% non-structured conformations. The more structured elements are usually concentrated in the catalytic C-terminal domain of the protein, while the more flexible and unstructured elements are grouped in the regulatory N-terminal domain.<ref> Chehin, R., M. Thorolfsson, PM. Knappskog, A. Martinez, T. Flatmark, JL. Arrondo, and A. Muga,Domain structure and stability of human phenylalanine hydroxylase inferred from infrared spectroscopy[http://www.ncbi.nlm.nih.gov/pubmed/9490012]</ref>  

'''Catalytic Domain'''

The catalytic domain 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.