SPARX, a new environment for Cryo-EM image processing (original) (raw)
Related papers
Journal of Structural Biology, 2011
Automated data acquisition expedites structural studies by electron microscopy and it allows to collect data sets of unprecedented size and consistent quality. In electron tomography it greatly facilitates the systematic exploration of large cellular landscapes and in single particle analysis it allows to generate data sets for an exhaustive classification of coexisting molecular states. Here we describe a novel software philosophy and architecture that can be used for a great variety of automated data acquisition scenarios. Based on our original software package TOM, the new TOM(2) package has been designed in an object-oriented way. The whole program can be seen as a collection of self-sufficient modules with defined relationships acting in a concerted manner. It subdivides data acquisition into a set of hierarchical tasks, bonding data structure and the operations to be performed tightly together. To demonstrate its capacity for high-throughput data acquisition it has been used in conjunction with instrumentation combining the latest technological achievements in electron optics, cryogenics and robotics. Its performance is demonstrated with a single particle analysis case study and with a batch tomography application.
Scipion3: A workflow engine for cryo-electron microscopy image processing and structural biology
Biological Imaging
Image-processing pipelines require the design of complex workflows combining many different steps that bring the raw acquired data to a final result with biological meaning. In the image-processing domain of cryo-electron microscopy single-particle analysis (cryo-EM SPA), hundreds of steps must be performed to obtain the three-dimensional structure of a biological macromolecule by integrating data spread over thousands of micrographs containing millions of copies of allegedly the same macromolecule. The execution of such complicated workflows demands a specific tool to keep track of all these steps performed. Additionally, due to the extremely low signal-to-noise ratio (SNR), the estimation of any image parameter is heavily affected by noise resulting in a significant fraction of incorrect estimates. Although low SNR and processing millions of images by hundreds of sequential steps requiring substantial computational resources are specific to cryo-EM, these characteristics may be sh...
CM01: a facility for cryo-electron microscopy at the European Synchrotron
Acta Crystallographica Section D: Structural Biology, 2019
Recent improvements in direct electron detectors, microscope technology and software provided the stimulus for a 'quantum leap' in the application of cryoelectron microscopy in structural biology, and many national and international centres have since been created in order to exploit this. Here, a new facility for cryo-electron microscopy focused on single-particle reconstruction of biological macromolecules that has been commissioned at the European Synchrotron Radiation Facility (ESRF) is presented. The facility is operated by a consortium of institutes co-located on the European Photon and Neutron Campus and is managed in a similar fashion to a synchrotron X-ray beamline. It has been open to the ESRF structural biology user community since November 2017 and will remain open during the 2019 ESRF-EBS shutdown. feature articles Acta Cryst. (2019). D75, 528-535 Kandiah et al. CM01 529 feature articles
XMIPP: a new generation of an open-source image processing package for electron microscopy
X-windows based microscopy image processing package (Xmipp) is a specialized suit of image processing programs, primarily aimed at obtaining the 3D reconstruction of biological specimens from large sets of projection images acquired by transmission electron microscopy. This public-domain software package was introduced to the electron microscopy field eight years ago, and since then it has changed drastically. New methodologies for the analysis of single-particle projection images have been added to classification, contrast transfer function correction, angular assignment, 3D reconstruction, reconstruction of crystals, etc. In addition, the package has been extended with functionalities for 2D crystal and electron tomography data. Furthermore, its current implementation in C++, with a highly modular design of well-documented data structures and functions, offers a convenient environment for the development of novel algorithms. In this paper, we present a general overview of a new generation of Xmipp that has been re-engineered to maximize flexibility and modularity, potentially facilitating its integration in future standardization efforts in the field. Moreover, by focusing on those developments that distinguish Xmipp from other packages available, we illustrate its added value to the electron microscopy community.
Scipion web tools: Easy to use cryo-EM image processing over the web
Protein Science
Macromolecular structural determination by Electron Microscopy under cryogenic conditions is revolutionizing the field of structural biology, interesting a large community of potential users. Still, the path from raw images to density maps is complex, and sophisticated image processing suites are required in this process, often demanding the installation and understanding of different software packages. Here, we present Scipion Web Tools, a web-based set of tools/workflows derived from the Scipion image processing framework, specially tailored to nonexpert users in need of very precise answers at several key stages of the structural elucidation process.
Routine Collection of High-Resolution cryo-EM Datasets Using 200 KV Transmission Electron Microscope
Journal of Visualized Experiments, 2022
Cryo-electron microscopy (cryo-EM) has been established as a routine method for protein structure determination during the past decade, taking an ever-increasing share of published structural data. Recent advances in TEM technology and automation have boosted both the speed of data collection and quality of acquired images while simultaneously decreasing the required level of expertise for obtaining cryo-EM maps at sub-3 Å resolutions. While most of such high-resolution structures have been obtained using state-of-the-art 300 kV cryo-TEM systems, high-resolution structures can be also obtained with 200 kV cryo-TEM systems, especially when equipped with an energy filter. Additionally, automation of microscope alignments and data collection with real-time image quality assessment reduces system complexity and assures optimal microscope settings, resulting in increased yield of high-quality images and overall throughput of data collection. This protocol demonstrates the implementation of recent technological advances and automation features on a 200 kV cryo-transmission electron microscope and shows how to collect data for the reconstruction of 3D maps that are sufficient for de novo atomic model building. We focus on best practices, critical variables, and common issues that must be considered to enable the routine collection of such high-resolution cryo-EM datasets. Particularly the following essential topics are reviewed in detail: i) automation of microscope alignments, ii) selection of suitable areas for data acquisition, iii) optimal optical parameters for high-quality, high-throughput data collection, iv) energy filter tuning for zero-loss imaging, and v) data management and quality assessment. Application of the best practices and improvement of achievable resolution using an energy filter will be demonstrated on the example of apo-ferritin that was reconstructed to 1.6 Å, and
Introduction to high-resolution cryo-electron microscopy
Postepy biochemii
For many years two techniques have dominated structural biology - X-ray crystallography and NMR spectroscopy. Traditional cryo-electron microscopy of biological macromolecules produced macromolecular reconstructions at resolution limited to 6-10 Å. Recent development of transmission electron microscopes, in particular the development of direct electron detectors, and continuous improvements in the available software, have led to the "resolution revolution" in cryo-EM. It is now possible to routinely obtain near-atomic-resolution 3D maps of intact biological macromolecules as small as ~100 kDa. Thus, cryo-EM is now becoming the method of choice for structural analysis of many complex assemblies that are unsuitable for structure determination by other methods.
Journal of Chemical Information and Modeling, 2020
Cryo-electron microscopy (cryo-EM) single particle analysis has come a long way in achieving atomic-level resolution when imaging biomolecules. In order to obtain the best possible three-dimensional structure in cryo-EM, many parameters have to be carefully considered. Here we address the often-overlooked parameter of the pixel size, which describes the magnification of the image produced by the experiment. While efforts are made to refine and validate this parameter in the analysis of cryo-EM experimental data, there is no systematic protocol in place. Since the pixel size parameter can have an impact on the resolution and accuracy of a cryo-EM map, and the atomic resolution, three-dimensional structure models derived from it, we propose a computational protocol to estimate the appropriate pixel size parameter. In our protocol, we fit and refine atomic structures against cryo-EM map at multiple pixel sizes. The resulting fitted and refined structures are evaluated using the GOAP (Generalized Orientation-Dependent, All-atom Statistical Potential) score, which we found to perform better than other commonly used functions, such as Molprobity and the correlation coefficient from refinement. Finally, we describe the efficacy of this protocol in retrieving appropriate pixel sizes for several examples; simulated data based on yeast elongation factor 2, and experimental data from Gro-EL chaperone, beta-galactosidase and the TRPV1 ion channel.
Automated cryo-electron microscopy
Proceedings IEEE International Symposium on Biomedical Imaging
Cryo-electron microscopy is widely viewed as a uniquely powerful method for the study of membrane proteins and large macromolecular complexes-subjects that are viewed as extremely challenging or impossible to study using x-ray or NMR methods. Although the methodology of molecular microscopy has enormous potential, it is time consuming and labor intensive. Our group has done extensive work to automate image acquisition and processing for cryo-EM. In this paper we will provide an overview of our automated system, called Leginon, and present results where we used tobacco mosaic virus (TMV) as a proof of concept.