Structural characterization of plum pox virus by cryo-electron microscopy.

Area of Science:

• Plant Virology
• Structural Biology
• Biochemistry

Background:

• Plum pox virus (PPV) is a major pathogen affecting Prunus species, causing substantial economic damage to fruit crops worldwide.
• Understanding PPV's structure is crucial for developing effective control strategies against this significant agricultural threat.

Purpose of the Study:

• To determine the high-resolution structure of Plum pox virus (PPV) using cryo-electron microscopy (cryo-EM).
• To elucidate the coat protein (CP) assembly, RNA encapsidation, and post-translational modifications of PPV.

Main Methods:

• High-resolution cryo-electron microscopy (cryo-EM) for structural determination.
• Mass spectrometry for identifying post-translational modifications.
• In silico analysis for predicting protein structural properties.

Main Results:

• A 2.9 Å resolution structure of the filamentous PPV virion was reconstructed, showing helical assembly of the coat protein (CP) around the ssRNA genome.
• The CP core structure is conserved among potyviruses, with identified RNA binding sites and inter-subunit interactions involving a disordered N-terminal arm.
• Mass spectrometry revealed extensive post-translational modifications, mainly phosphorylation, in the flexible N-terminal region of the CP.

Conclusions:

• The study provides unprecedented structural insights into PPV architecture and assembly.
• The findings highlight the role of the disordered N-terminal arm and post-translational modifications in CP function.
• This structural information serves as a foundation for future research and the development of antiviral strategies against PPV.