DM: a simple solution to suppress air-water interface interactions in cryo-EM

Area of Science:

• Structural Biology
• Biochemistry
• Biophysics

Background:

• The air-water interface (AWI) presents a major challenge in cryo-electron microscopy (cryo-EM), causing protein adsorption, denaturation, and preferred particle orientations.
• These AWI-induced artifacts hinder routine high-resolution structure determination of macromolecules.

Purpose of the Study:

• To introduce a broadly applicable strategy to mitigate AWI-driven artifacts in cryo-EM sample preparation.
• To evaluate the efficacy of n-decyl-β-D-maltopyranoside (DM) as an additive for improving cryo-EM data quality.

Main Methods:

• A mild non-ionic detergent, n-decyl-β-D-maltopyranoside (DM), was added at low millimolar concentrations immediately prior to vitrification.
• The impact of DM on particle distribution, structural integrity, and reconstruction quality was assessed across diverse macromolecular systems.

Main Results:

• DM addition consistently suppressed AWI-driven artifacts, leading to improved angular sampling and reduced structural damage.
• High-resolution reconstructions were achieved for challenging targets like Nucleophosmin 1 pentamer, hemagglutinin, and transthyretin.
• DM prevented denaturation in aldolase and stabilized its C-terminus, demonstrating its protective effects.

Conclusions:

• n-decyl-β-D-maltopyranoside (DM) effectively passivates deleterious air-water interface interactions without compromising particle integrity.
• DM is a valuable additive for enhancing the robustness and quality of single-particle cryo-EM sample preparation.