MiLoPYP: self-supervised molecular pattern mining and particle localization in situ Cryo-electron tomography (CET) allows the routine visualization of cellular landscapes in three dimensions at nanometer-range resolutions. When combined with single-particle tomography (SPT), it is possible to obtain near-atomic resolution structures of frequently occurring macromolecules within their native environment. Two outstanding challenges associated with CET/SPT are the automatic identification and…
Advances in cryo-ET data processing: meeting the demands of visual proteomics Cryogenic electron tomography (cryo-ET), a method that enables the viewing of biomolecules in near-native environments at high resolution, is rising in accessibility and applicability. Over the past several years, once slow sample preparation and data collection procedures have seen innovations which enable rapid collection of the large datasets…
Accurate size-based protein localization from cryo-ET tomograms Cryo-electron tomography (cryo-ET) combined with sub-tomogram averaging (STA) allows the determination of protein structures imaged within the native context of the cell at near-atomic resolution. Particle picking is an essential step in the cryo-ET/STA image analysis pipeline that consists in locating the position of proteins within crowded cellular tomograms so that they…
Joint micrograph denoising and protein localization in cryo-electron microscopy Cryo-electron microscopy (cryo-EM) is an imaging technique that allows the visualization of proteins and macromolecular complexes at near-atomic resolution. The low electron doses used to prevent radiation damage to the biological samples result in images where the power of noise is 100 times stronger than that of the signal. Accurate…
nextPYP: a comprehensive and scalable platform for characterizing protein variability in situ using single-particle cryo-ET Single-particle cryo-electron tomography (SP-CET) is an emerging technique capable of determining the structure of proteins imaged within the native context of cells at molecular resolution. While high-throughput techniques for sample preparation and tilt-series acquisition are beginning to provide sufficient data to allow structural studies…
Multiple-image super-resolution of cryo-electron micrographs based on deep internal learning Single-particle cryo-electron microscopy (cryo-EM) is a powerful imaging modality capable of visualizing proteins and macromolecular complexes at near-atomic resolution. The low electron-doses used to prevent radiation damage to the biological samples, however, result in images where the power of the noise is 100 times greater than the power of…
Accurate Detection of Proteins in Cryo-Electron Tomograms from Sparse Labels Cryo-electron tomography (CET) combined with sub-volume averaging (SVA), is currently the only imaging technique capable of determining the structure of proteins imaged inside cells at molecular resolution. To obtain high-resolution reconstructions, sub-volumes containing randomly distributed copies of the protein of interest need be identified, extracted and subjected to SVA,…
High-resolution structure determination using high-throughput electron cryo-tomography The low throughput characteristic of tomographic data acquisition combined with the complex data-analysis pipeline that is required to obtain high-resolution maps, has limited the applicability of this technique to favorable samples or to resolutions that are too low to provide useful mechanistic information. Recently, beam image-shift electron cryo-tomography (BISECT), a strategy to…
Data-driven determination of number of discrete conformations in single-particle cryo-EM Single-particle cryo-EM can be used to image heterogeneous samples containing multiple molecular species, different oligomeric states or distinct conformations. This, however, requires expert-user knowledge and trial-and-error experimentation to determine the correct number of conformations present in a mixture. Here, we propose an approach to address the problem of automatically…
Automated systematic evaluation of cryo-EM specimens with SmartScope We present SmartScope, the first framework to streamline, standardize, and automate specimen evaluation in cryo-electron microscopy. SmartScope employs deep-learning-based object detection to identify and classify features suitable for imaging, allowing it to perform thorough specimen screening in a fully automated manner. A web interface provides remote control over the automated operation…
Cryo-ZSSR: multiple-image super-resolution based on deep internal learning We present a multiple-image super-resolution (SR) algorithm based on deep internal learning designed specifically to work under low-SNR conditions typical of cryo-EM data. Our approach leverages the internal image statistics of cryo-EM movies and does not require training on ground-truth data. When applied to a single-particle dataset of apoferritin, we show…
Beam image-shift accelerated data acquisition for near-atomic resolution single-particle cryo-electron tomography To overcome the inherent low-throughput characteristic of CET data collection, improve the resolution of SVA and extend its application to a wider set of samples including low molecular weight targets, here, we: (1) use beam-image shift navigation to multiply the number of regions of interest imaged at each…
Mathematical Theory, Computational Challenges, and Opportunities Structural biology studies the structure and dynamics of macromolecules to broaden our knowledge about the mechanisms of life and impact the drug-discovery process. Owing to recent groundbreaking developments, chiefly in hardware technologies and data processing techniques, many new molecular structures have been elucidated to near-atomic resolutions using cryo-EM. The main goal of this article…
Unsupervised particle sorting for high-resolution single-particle cryo-EM Single-particle cryo-Electron Microscopy (EM) has become a popular technique for determining the structure of challenging biomolecules that are inaccessible to other technologies. Recent advances in automation, both in data collection and data processing, have significantly lowered the barrier for non-expert users to successfully execute the structure determination workflow. Many critical data processing…
Atomic Resolution Cryo-EM Structure of B-galactosidase We report methods to account for radiation damage and local changes in defocus and image drift, enabling visualization of atomic resolution features in a cryo-EM density map of inhibitor-bound b-galactosidase, and measuring of local flexibility of the bound inhibitor using constrained molecular dynamics simulations. Structure, 26(6), 2018.