Structural characterization of the HCoV-229E fusion core

Area of Science:

• Structural Biology
• Virology
• Drug Discovery

Background:

• The HCoV-229E spike (S) protein facilitates viral entry by mediating cell attachment and membrane fusion.
• The S2 subunit of the spike protein contains heptad repeat regions (HR1 and HR2) crucial for fusion.
• Understanding the structure of these HR regions is key to inhibiting viral fusion.

Purpose of the Study:

• To determine the crystal structure of the HCoV-229E fusion core.
• To analyze the sequence and structural conservation of HR1 and HR2 domains.
• To investigate the interactions within the fusion core.

Main Methods:

• Design and expression of a recombinant fusion core protein.
• Crystallization and X-ray diffraction analysis to solve the protein structure (2.45 Å resolution).
• Sequence alignment and structural analysis to characterize HR1-HR2 binding.

Main Results:

• The crystal structure of the HCoV-229E fusion core was determined.
• HR1 and HR2 sequences and structures exhibit high conservation, particularly in HR2 residues.
• Detailed analysis revealed complementary hydrophobic and polar interactions between HR1 and HR2 helices, forming seven heptad repeats.

Conclusions:

• The determined structure provides insights into the molecular mechanisms of HCoV-229E membrane fusion.
• The high conservation of core residues suggests potential targets for antiviral therapies.
• This knowledge could facilitate the design of small molecule or polypeptide drugs to inhibit viral fusion and infection.