Reconstructing an icosahedral virus from single-particle diffraction experiments.

Area of Science:

• Structural Biology
• Biophysics
• X-ray Crystallography

Background:

• Experimental data from single-particle scattering using free electron lasers (FELs) are emerging.
• Initial experiments focus on large biomolecules like viruses, yielding low-resolution diffraction patterns.
• "Diffract-and-destroy" experiments capture data before sample degradation.

Purpose of the Study:

• To develop a method for identifying icosahedral particles from scattering data.
• To enable the reconstruction of 3D virus structures from multiple diffraction patterns.
• To demonstrate the algorithm's efficacy using a simulated virus.

Main Methods:

• A simple test analyzing angular correlations in diffraction data to confirm icosahedral symmetry.
• An efficient algorithm to combine diffraction data from multiple randomly oriented particles.
• Simulation using the satellite tobacco necrosis virus (STNV) with known atomic coordinates.

Main Results:

• Successfully demonstrated a method to identify icosahedral scattering.
• Validated an algorithm capable of reconstructing 3D structures from simulated FEL data.
• The STNV simulation yielded a complete 3D image reconstruction.

Conclusions:

• The proposed method reliably identifies icosahedral particles in FEL scattering experiments.
• The algorithm efficiently reconstructs 3D virus structures from limited, noisy diffraction data.
• This approach advances structural biology by enabling high-resolution imaging of viruses.