New computational technique extends cryo‑EM resolution beyond Nyquist limit

Cryo-electron microscopy (cryo‑EM) has emerged as a cornerstone technique for resolving the three‑dimensional structures of proteins, viruses, and complex macromolecular assemblies at near‑atomic detail. The attainable resolution, however, is bounded by the Nyquist sampling frequency, which is set by the combination of detector pixel size and the microscope’s magnification. When the data reach this physical ceiling, the image sampling no longer captures the finest structural features, and the resolution plateaus despite further data collection.

To surpass the Nyquist limit, investigators must recollect the same specimen at a higher magnification, effectively shrinking the pixel size on the sample. This adjustment requires additional microscope time, increases the volume of raw data that must be stored, and typically reduces the number of particles that can be recorded per micrograph. Consequently, researchers must balance the need for higher resolution against practical constraints such as instrument availability, data storage capacity, and throughput.

In practice, the decision to re‑image at higher magnification is driven by the scientific question at hand and the desired resolution. While cryo‑EM continues to push the boundaries of structural biology, its resolution gains are ultimately constrained by the Nyquist criterion, making careful experimental planning essential for efficient use of advanced electron microscopes.