Beam image-shift accelerated data acquisition for near-atomic resolution single-particle cryo-electron tomography

Area of Science:

• Structural Biology
• Cryo-Electron Microscopy
• Biophysics

Background:

• In-situ structural studies using cryo-electron tomography (cryo-ET) allow atomic model determination of macromolecules within their native cellular environment.
• Current cryo-ET methods are limited by slow data collection speeds due to the need for error correction during mechanical specimen navigation.

Purpose of the Study:

• To develop and validate an accelerated data acquisition and processing strategy for cryo-ET.
• To significantly enhance the speed and resolution of cryo-ET for in-situ structural analysis.

Main Methods:

• Implementation of beam-image shift to image multiple areas per stage position, increasing data collection efficiency.
• Integration of geometrical constraints during imaging for precise targeting.
• Per-tilt astigmatic contrast transfer function (CTF) estimation and data-driven exposure weighting for improved resolution.

Main Results:

• Achieved up to a tenfold increase in data collection speed compared to existing methods.
• Developed the beam image-shift electron cryo-tomography (BISECT) approach.
• Determined the structure of a ~300 kDa target at 3.6 Å resolution, with clear side-chain density.

Conclusions:

• The BISECT approach significantly accelerates cryo-ET data collection and improves map resolution.
• This method enhances the practical utility of cryo-ET for in-situ structural studies of cellular macromolecules.