Heterotrimeric coiled coils with core residue urea side chains

Area of Science:

• Protein engineering
• Biochemistry
• Structural biology

Background:

• Coiled coils are common protein structures.
• Designing stable coiled coils is crucial for various applications.
• Understanding the factors governing coiled coil stability is an ongoing challenge.

Purpose of the Study:

• To engineer novel coiled coil heterotrimers with high thermal stability.
• To explore the impact of synthetic side chains on coiled coil formation.
• To investigate the role of core residue charge pairings in trimeric coiled coil stability.

Main Methods:

• Synthesis of peptides with varying core residue properties, including synthetic side chains.
• Thermal denaturation assays to determine melting temperatures (Tm).
• Analysis of coiled coil structure and stability based on core residue interactions.

Main Results:

• Several coiled coil heterotrimers with Tm values exceeding 43°C were successfully designed.
• Introduction of synthetic side chains, such as monosubstituted ureas, broadened the scope of usable core residues.
• Trimeric coiled coils were found to be intolerant to guanidine-guanidine contacts, even with compensating charges, a contrast to dimeric systems.

Conclusions:

• The study significantly expands the repertoire of feasible coiled coil designs.
• Synthetic side chains offer new avenues for tuning coiled coil stability and properties.
• Specific constraints exist for charge pairings in trimeric coiled coils, distinct from dimeric counterparts.