Providence Virus (PrV) is a non-envoloped,
T = 4 icosahedral beta-tetravirus that undergoes autocatalytic cleavage of its coat protein precursor after capsid assembly.
This is also a well characterized function of Nudaurelia capensis ω virus (NωV), a member of the related omegatetraviruses,
whose x-ray structure has been determined. Virus-like particle (VLP) production of PrV in a recombinant baculovirus expression
system was attempted to obtain high VLP yields for comparison of structural and autocatalytic active site properties between
these virus groups. This resulted in insoluble aggregates of PrV coat protein even though NωV VLPs have been successfully
produced in the same system. Betatetraviruses may be more dependent on compartmentalization and availability of their full-length
genome for proper folding and assembly. However, crystals were grown of limited quantities of authentic PrV produced in cell
culture and a partial X-ray data set collected to 3.8 Å resolution. The virus particle position and orientation in the unit
cell was determined by space group consideration and rotation function analysis. A phasing model, based on NωV, was developed
to initiate the structure solution of PrV.