Based on the provided reference, an amino acid hinge region is a specific segment of a protein that serves to connect two distinct functional domains.
Definition and Location
In the context of the Vitamin D Receptor (VDR) protein as described, the hinge region is a crucial link. It links the DBD (DNA-binding domain) to the LBD (ligand-binding domain).
- Residue Range: This specific hinge region encompasses amino acid residues 88–120.
This structural connection allows the different domains of the protein to function together effectively.
Functional Significance
The hinge region is not merely a passive connector; it plays a vital role in the protein's function. The reference highlights specific areas within this region that are critical for activity.
- Key Basic Stretches: Two particular stretches of basic amino acids within the hinge region are essential:
- Residues 102–104
- Residues 109–111
These basic stretches are explicitly stated as being required for transactivation (the process by which the protein activates gene expression) and binding to VDREs (Vitamin D Response Elements), which are specific DNA sequences.
Furthermore, these areas may contribute to:
- Heterodimerization: The process where the VDR protein pairs with another protein (like RXR) to form a functional complex.
- Other necessary VDR functions: Contributing to the overall ability of VDR to regulate gene expression.
| Characteristic | Description |
|---|---|
| Primary Role | Links DBD to LBD |
| Amino Acid Range | 88–120 |
| Key Functional Sites | Residues 102–104 and 109–111 (basic amino acids) |
| Required For | Transactivation, Binding to VDREs |
| Potential Contribution | Heterodimerization, Other VDR functions for transactivation |
In summary, the amino acid hinge region, as described for the VDR, is a specific amino acid segment linking the DNA-binding and ligand-binding domains. It contains critical basic amino acid stretches essential for DNA binding and gene activation.
