3D Structure of PheOH

CPK Color Scheme

On this page, you can see the tetrameric form of Phenylalanine Hydroxylase. Click the different buttons to learn more about its structure and function. You can hold shift and drag to zoom in or out. You can also hold shift and double click to move the molecule and center it as you wish.

Reset and spin the PheOH molecule.

Although PheOH consists of four identical subunits, click here to see just one of the subunits. Looking at just one subunit first allows us to easily distinguish the different domains within each subunit.

PheOH is comprised of 3 distinct domains: the tetramerization domain (yellow), the catalytic domain (blue), and the regulatory domain (not available in this PDB file).

Now look at all four subunits of the PheOH molecule together. Again observe the tetramerization domain (yellow) and the catalytic domain (blue).

PheOH is made of four identical subunits. The four alpha helices that make up part of the tetramerization domain form coiled-coil motifs to hold the protein together. Zoom in and observe this interaction.

The active site of the protein consists of primarily hydrophobic amino acids (red) because Phenylalanine is a hydrophobic amino acid. All other amino acids are shown in white. The presence of hydrophobic amino acids creates a favorable pocket deep within the protein where hydroxylation can occur.

View the active site up close and cutaway. Hydrophobic amino acids are red, while all others remain white.

Within the catalytic site there is a single Iron atom (green). The iron is thought to somehow contribute to the overall stability of the protein when it forms a substrate-enzyme complex. Zoom in on the Iron atom and the surrounding area.

Reference: Fusetti F, Erlandsen H, Flatmark T, Stevens R. 1998 March. Structure of Tetrameric Human Phenylalanine Hydroxylase and Its Implications for Phenylketonuria. Journal of Biological Chemistry 273: 16962-16967.

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