Beef tallow injection matrix for serial crystallography

Area of Science:

• Structural Biology
• Biophysics
• Crystallography

Background:

• Serial crystallography (SX) visualizes molecular dynamics at room temperature, minimizing radiation damage.
• Stable sample delivery is crucial for SX, with viscous media reducing sample consumption.
• Optimizing sample delivery media is essential for enhancing SX experimental efficiency.

Purpose of the Study:

• To introduce and evaluate beef tallow as a novel sample delivery medium for serial crystallography.
• To assess the stability and performance of beef tallow in SX experiments.
• To determine the feasibility of using beef tallow for room-temperature structure determination.

Main Methods:

• Preparation of beef tallow by heat treatment and purification of cattle fats.
• Application of beef tallow as an injection matrix for SX experiments.
• Structure determination of lysozyme and glucose isomerase embedded in beef tallow at room temperature.

Main Results:

• Beef tallow demonstrated a highly stable injection stream at room temperature with low flow rates (<10 nL/min).
• High-resolution structures of lysozyme (1.55 Å) and glucose isomerase (1.60 Å) were successfully determined.
• While exhibiting higher background scattering than other fat-based media, beef tallow's scattering was negligible for data processing.

Conclusions:

• Beef tallow is a viable and effective sample delivery medium for serial crystallography.
• This matrix facilitates room-temperature structure determination and is suitable for experiments above room temperature.
• The use of beef tallow expands the options for optimizing sample delivery in SX.