Single mimivirus particles intercepted and imaged with an X-ray laser

Area of Science:

• Structural biology
• X-ray science
• Biophysics

Background:

• X-ray lasers provide unprecedented brightness and coherence.
• Short X-ray pulses can outpace sample damage mechanisms.
• Diffraction imaging of non-crystalline samples allows for direct phase retrieval.

Purpose of the Study:

• To demonstrate high-resolution imaging of a single biological particle using a single X-ray pulse.
• To assess the feasibility of X-ray free-electron lasers for structural determination of biomolecules.
• To overcome radiation damage limitations in X-ray diffraction studies.

Main Methods:

• Utilized the Linac Coherent Light Source (LCLS), a hard-X-ray free-electron laser.
• Injected a single mimivirus particle into the pulsed X-ray beam.
• Obtained a single diffraction pattern from the non-crystalline biological sample.
• Reconstructed the exit wavefront to determine the particle's structure.

Main Results:

• Achieved 32-nm resolution imaging of a single mimivirus particle in a single exposure.
• The sample experienced extreme heating (>100,000 K) but showed no measurable damage post-exposure.
• Reconstruction revealed an inhomogeneous distribution of dense material within the virion.

Conclusions:

• Single X-ray pulses from free-electron lasers can yield high-quality diffraction data from biological samples.
• This technique offers a pathway to visualize biological structures at the nanoscale without significant radiation damage.
• Future advancements in pulse intensity and focusing are expected to further enhance resolution.