Structural Analysis of VDR Complex with ZK168281 Antagonist

Area of Science:

• Molecular biology
• Structural biology
• Biochemistry

Background:

• Vitamin D receptor (VDR) antagonists inhibit VDR transcriptional regulation.
• VDR antagonists function by preventing the activation function helix 12 from adopting its active conformation.

Purpose of the Study:

• To elucidate the structural mechanism by which the VDR antagonist ZK168281 inhibits VDR function.
• To investigate the impact of ZK168281 on VDR C-terminal region folding.

Main Methods:

• X-ray crystallography of the zebrafish VDR ligand-binding domain in complex with ZK168281.
• Hydrogen-deuterium exchange mass spectrometry (HDX-MS) in solution.

Main Results:

• The crystal structure reveals that ZK168281 binding prevents the optimal folding of the VDR C-terminal region.
• HDX-MS confirmed that the antagonist interferes with VDR C-terminal region folding in solution.

Conclusions:

• ZK168281 antagonizes VDR transcriptional activity by disrupting the conformational flexibility of the VDR C-terminal region.
• Understanding these structural interactions provides insights into VDR antagonist design.