Improved cryo-EM reconstruction of sub-50 kDa complexes using 2D template matching.
4 affiliations
- 1RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, United States.
- 2Howard Hughes Medical Institute, Worcester, United States.
- 3Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.
- 4Morgridge Institute for Research, Madison, United States.
Abstract
Visualizing the structures of small proteins and complexes has been a longstanding challenge in single-particle cryo-electron microscopy (cryo-EM). Some of these targets have been successfully resolved by binding to antibody fragments (Fabs) or fusing with external scaffolds to increase their size. Recent advances in conventional single-particle techniques have enabled the determination of an increasing number of structures smaller than 100 kDa, achieving resolutions relevant to drug research. Compared to X-ray crystallography, cryo-EM preserves the near-native states of biomolecules, can resolve structural heterogeneity, and has the potential to apply to a wide range of targets. In this work, we demonstrate that the alignment and reconstruction of small macromolecular complexes can be improved using high-resolution structures as priors, combined with 2D template matching. Using this method, we reconstructed a previously intractable ∼43 kDa protein kinase and improved the density of its ligand-binding site. Our theoretical analysis predicts that this method can further extend single-particle cryo-EM to important drug-binding complexes well below 50 kDa.
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BibTeX
@article{zhang2026improved,
title = {{Improved cryo-EM reconstruction of sub-50 kDa complexes using 2D template matching.}},
author = {Kexin Zhang and Timothy Grant and Nikolaus Grigorieff},
journal = {ELife},
year = {2026},
month = oct,
doi = {10.7554/elife.109790},
url = {https://europepmc.org/article/MED/42930231},
note = {CC BY},
}
RIS
TY - JOUR
TI - Improved cryo-EM reconstruction of sub-50 kDa complexes using 2D template matching.
AU - Kexin Zhang
AU - Timothy Grant
AU - Nikolaus Grigorieff
PY - 2026
DA - 2026/10/26
JO - ELife
DO - 10.7554/elife.109790
UR - https://europepmc.org/article/MED/42930231
AB - Visualizing the structures of small proteins and complexes has been a longstanding challenge in single-particle cryo-electron microscopy (cryo-EM). Some of these targets have been successfully resolved by binding to antibody fragments (Fabs) or fusing with external scaffolds to increase their size. Recent advances in conventional single-particle techniques have enabled the determination of an increasing number of structures smaller than 100 kDa, achieving resolutions relevant to drug research. Compared to X-ray crystallography, cryo-EM preserves the near-native states of biomolecules, can resolve structural heterogeneity, and has the potential to apply to a wide range of targets. In this work, we demonstrate that the alignment and reconstruction of small macromolecular complexes can be improved using high-resolution structures as priors, combined with 2D template matching. Using this method, we reconstructed a previously intractable ∼43 kDa protein kinase and improved the density of its ligand-binding site. Our theoretical analysis predicts that this method can further extend single-particle cryo-EM to important drug-binding complexes well below 50 kDa.
SN - 2050-084X
ER -