Structural basis of mpox virus A30/H2 subcomplex formation

Area of Science:

• Virology
• Structural Biology
• Immunology

Background:

• Mpox virus (MPXV) poses a significant global public health threat due to its continuous spread.
• MPXV entry into host cells involves a multimeric protein complex known as the entry-fusion complex (EFC).
• The A30 and H2 proteins are crucial components of the MPXV EFC, identified as an early interaction pair vital for viral entry.

Purpose of the Study:

• To determine the crystal structure of the MPXV A30/H2 subcomplex.
• To elucidate the molecular interactions governing the formation and function of the A30/H2 subcomplex.
• To evaluate the immunogenic potential of a novel H2-A30 fusion protein for potential vaccine development.

Main Methods:

• Tandem-fusion strategy for protein expression and crystallization.
• X-ray crystallography to determine the high-resolution structure of the MPXV A30/H2 subcomplex.
• In vitro binding assays to identify key residues and interactions in subcomplex formation.

Main Results:

• The crystal structure of the MPXV A30/H2 subcomplex was determined, revealing significant conformational changes in A30 upon H2 binding.
• Structural analysis identified an extended intersubunit interface with highly conserved intermolecular interactions.
• In vitro data confirmed key residues and elements essential for A30/H2 subcomplex assembly.
• The H2-A30 fusion protein demonstrated superior immunogenicity, inducing potent neutralizing antibody responses compared to individual components.

Conclusions:

• The determined structure provides critical insights into poxvirus entry-fusion complex assembly.
• Understanding A30/H2 interactions is vital for comprehending MPXV entry mechanisms.
• The H2-A30 fusion protein represents a promising candidate for developing effective MPXV immunogens and vaccines.