Three-dimensional single-particle imaging using angular correlations from X-ray laser data.

Area of Science:

• Biophysics
• Structural Biology
• X-ray Scattering

Background:

• Femtosecond X-ray pulses from X-ray free-electron lasers (XFELs) allow for room-temperature solution scattering experiments.
• These experiments capture snapshots of molecules frozen in space, yielding anisotropic scattering patterns.

Purpose of the Study:

• To present a novel method utilizing fluctuation X-ray scattering (FXS) data for determining low-resolution solution structures.
• To overcome limitations of standard small-angle scattering (SAS) by leveraging additional information from intensity fluctuations.

Main Methods:

• Conducting room-temperature solution scattering experiments using femtosecond X-ray pulses.
• Analyzing anisotropic scattering patterns and intensity fluctuations.
• Developing a method to reconstruct molecular structures from FXS data without symmetry or spatial restraints.

Main Results:

• The developed method successfully determined low-resolution solution structures.
• Validation with theoretical data from representative molecules was achieved.
• Successful application to experimental data for nanoparticle reconstruction at the Linac Coherent Light Source (LCLS).

Conclusions:

• Fluctuation X-ray scattering provides a powerful approach for structural determination of macromolecules in solution.
• This method reduces ambiguities inherent in traditional solution scattering techniques.
• The presented method offers a pathway to elucidate complex molecular structures without prior assumptions.