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User:John Hangasky/Sandbox 1
From Proteopedia
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| 1h2l, resolution 2.25Å () | |||||||||
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| Ligands: | , , | ||||||||
| Related: | 1d7g, 1h2k, 1h2m, 1h2n, 1l8c, 1lm8, 1lqb | ||||||||
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| Resources: | FirstGlance, OCA, RCSB, PDBsum | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Factor Inhibiting HIF
Hypoxia Inducible Factor (HIF)is a transcription activator that regulates over 100 genes, many of which are important for development. HIF has been found to be over expressed in many cancers. Factor Inhibing HIF (FIH) is a non-heme Iron (II) α-ketoglutarate dependent asparaginyl hydroxylase that regulates HIF. In normoxic conditions (high oxygen concenrations), molecular oxygen is used to hydroxylate HIF, preventing HIF from binding to p300, a transcription coactivator. However, in hypoxic conditions (low oxygen concentrations), this hydroxylation does not occur.
FIH binds to the C-terminal activation domain (CTAD) of HIF. This binding domain, , colored teal.
Active Site
The contains an iron II core. The iron core is coordinated by 2 histidine residues, an asparagine residue, α-ketoglutarate and one water molecule. α-ketoglutarate chelates in a bidentate manner, making the coordination number of the iron 6. In the depiction of the Histidines are colored blue, Aspartate is colored red, Iron is the white sphere, and α-KG is colored yellow. The sixth coordination site is usually occupied by water, not shown here.
Oxygen Channel
For FIH to modify its substrate, molecular oxygen must reach the active site. Since the active site is buried within the enzyme, oxygen must reach the active site via an oxygen channel. An has been proposed, leading to this active site.
