Lard Injection Matrix for Serial Crystallography

Area of Science:

• Structural Biology
• Biophysics
• Crystallography

Background:

• Serial crystallography (SX) uses X-ray free electron lasers or synchrotrons for room-temperature structure determination.
• SX enables the study of macromolecular structural dynamics through time-resolved experiments.
• Developing effective sample delivery media is crucial for advancing SX applications.

Purpose of the Study:

• To prepare and characterize a lard-based sample delivery medium for serial crystallography.
• To evaluate the stability and injectability of the lard medium.
• To assess the suitability of lard as a delivery medium in SX experiments.

Main Methods:

• Lard was processed via heat treatment and phase separation to remove impurities.
• The lard medium was characterized for stability and injectability at room temperature using a syringe needle.
• Serial millisecond crystallography experiments were conducted with proteins embedded in the lard medium.

Main Results:

• The lard-based medium demonstrated high stability and could be injected at flow rates below 200 nL/min.
• Room-temperature structures of lysozyme and glucose isomerase were determined at 1.75 and 1.80 Å resolution, respectively.
• The lard medium exhibited X-ray background scattering comparable to or lower than conventional media like shortenings and lipidic cubic phase.

Conclusions:

• A lard-based medium is a viable and effective option for sample delivery in serial crystallography.
• This method facilitates room-temperature structure determination with reduced radiation damage.
• The lard medium offers advantages in sample consumption and stability for SX experiments.