Diversifying particle-orientation distributions in cryo-EM with LEA protein additives

Area of Science:

• Structural biology
• Biochemistry

Background:

• Preferential particle orientation at the air-water interface (AWI) is a major challenge in cryo-electron microscopy (cryo-EM).
• This orientation bias often necessitates extensive optimization or specialized grid preparation techniques.
• Existing methods struggle to consistently achieve isotropic particle distributions.

Purpose of the Study:

• To investigate the potential of late embryogenesis abundant (LEA) proteins in mitigating AWI-induced sample damage.
• To determine if LEA proteins can resolve or improve particle orientation distributions in cryo-EM.
• To establish LEA proteins as practical additives for single-particle analysis.

Main Methods:

• Utilizing cryo-electron microscopy techniques.
• Applying late embryogenesis abundant (LEA) proteins to biological samples.
• Analyzing particle orientation distributions before and after LEA protein addition.

Main Results:

• Addition of LEA proteins was shown to reduce air-water interface (AWI)-induced sample damage.
• LEA proteins induced new or more isotropic particle orientation distributions.
• Samples previously suffering from orientation bias showed improved distributions with LEA proteins.

Conclusions:

• Late embryogenesis abundant (LEA) proteins are effective additives for cryo-EM.
• LEA proteins can alleviate AWI-induced damage and improve particle orientation.
• These findings offer a practical strategy to enhance single-particle analysis data quality.