Structure of Bombyx mori densovirus 1, a silkworm pathogen

Area of Science:

• Structural biology
• Virology
• Biochemistry

Background:

• Bombyx mori densovirus 1 (BmDNV-1) is a significant pathogen impacting the silk industry.
• Understanding viral structures is crucial for developing control strategies.

Purpose of the Study:

• To determine the near-atomic-resolution structure of the Bombyx mori densovirus 1 (BmDNV-1) virus-like particle.
• To compare the structural features of BmDNV-1 with other parvoviruses.

Main Methods:

• X-ray crystallography was employed to resolve the structure of recombinant BmDNV-1 virus-like particles.
• The resolution achieved was 3.1 Å.

Main Results:

• The structure reveals 60 copies of the VP3 coat protein forming the capsid.
• The VP3 protein exhibits a β-barrel jelly roll fold, common to many icosahedral viruses.
• Unique surface loops were observed, differing from other parvoviruses.
• A domain-swapped conformation of the N-terminal β-strand was identified, consistent with invertebrate parvoviruses.

Conclusions:

• This is the first near-atomic-resolution structure for a virus-like particle in the Iteravirus genus.
• The observed domain swapping suggests it is an evolutionarily conserved trait within the Densovirinae subfamily.