Molecule of the Month: Hypoxia-Inducible Factors
HIF-α is a molecular switch that responds to changing oxygen levels.
Exploring the Structure
Drugs that bind to the PHD enzymes are being evaluated for treatment of anemia. By blocking these enzymes, the drug tricks cells into thinking they need more oxygen, so they send signals to build more red blood cells. Initial structures of PHD2 enabled structure-based design of inhibitors of the enzyme (PDB entries 2g1m, 2g19), and a drug currently under evaluation, vadadustat, is shown here (PDB entry 5ox6). By comparing this to the structure of PHD2 bound to a small piece of HIF-α (PDB entry 3hqr), we can see that the investigational drug mimics binding of α-ketoglutarate to the enzyme (NOG is similar to α-ketoglutarate), and is big enough to block binding of the HIF-α proline.
Topics for Further Discussion
- There are many structures of FIH (factor inhibiting HIF) in the PDB archive if you would like to explore it and its interaction with substrates and inhibitors.
- The scissor-shaped DNA-binding domain of the HIF complex is termed “basic helix-loop-helix.” You can see other examples by searching for “bHLH” on the main PDB site.
December 2019, David Goodselldoi:10.2210/rcsb_pdb/mom_2019_12