Transcription factor allosteric regulation through substrate coordination to zinc

Area of Science:

• Synthetic biology
• Molecular biology
• Biotechnology

Background:

• Allosteric transcription factors (aTFs) are crucial regulatory proteins in biological systems.
• Understanding their mechanism is essential for advancing synthetic biology and genetic engineering.
• The UxuR protein serves as a model system to investigate aTF dynamics and function.

Purpose of the Study:

• To elucidate the mechanistic insights into the allosteric transcription factor UxuR.
• To investigate the impact of ligand binding on UxuR protein dynamics and conformation.
• To provide a foundation for engineering biological systems using aTFs.

Main Methods:

• Molecular dynamics (MD) simulations of UxuR in different states (free, bound to D-fructuronate, bound to D-glucuronate).
• Construction of a sensor plasmid for D-fructuronate detection in *Escherichia coli*.
• Site-directed mutagenesis to validate the role of specific residues and zinc coordination.

Main Results:

• Zinc coordination is essential for UxuR's function in gene expression de-repression.
• Flexible linker regions facilitate large movements of the N-terminal domains.
• Inducer (D-fructuronate) binding promotes an 'open' conformation with a negative surface charge on DNA-binding domains.
• Absence of inducer or binding of D-glucuronate results in 'closed' conformations with a positive surface charge.

Conclusions:

• Ligand-induced conformational changes in UxuR are critical for its function.
• The study provides detailed molecular insights into UxuR's allosteric regulation.
• These findings can guide the rational design of synthetic biology circuits and biotechnological applications.