Spontaneous Interconversion between Different Narrowly Defined Shapes of Rotavirus Double-Layered Particles Studied...

Area of Science:

• Structural Biology
• Virology
• Physical Chemistry

Background:

• Rotavirus double-layered particles (DLPs) are crucial viral structures.
• Understanding DLP conformation is key to viral assembly and stability.
• Previous studies hinted at structural variations but lacked real-time gas-phase analysis.

Purpose of the Study:

• To investigate the gas-phase conformations of rotavirus DLPs.
• To analyze the dynamics and reversibility of DLP structural interconversions.
• To correlate gas-phase structures with potential solution-phase conformations and VP6 protein loss.

Main Methods:

• High-resolution differential mobility analysis (DMA) of DLPs in the gas phase.
• Electrospray ionization from aqueous ammonium acetate solution.
• Real-time monitoring of particle conformations and interconversions.

Main Results:

• Up to seven distinct DLP conformations were resolved in the gas phase.
• Fast, reversible interconversions between these conformations were observed.
• Gas-phase DLPs showed a smaller diameter (60 nm) compared to solution (70 nm), suggesting structural changes and potential VP6 trimer quintet loss.

Conclusions:

• The observed gas-phase conformations likely originate from pre-existing conformations in solution.
• Incomplete DLPs, potentially lacking VP6 trimer quintets, may account for the observed structural diversity.
• The systematic observation of VP6 loss across multiple rotavirus types in ammonium acetate suggests this may be an electrolyte-specific feature.