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James Pulokas

Bio: James Pulokas is an academic researcher from Scripps Research Institute. The author has contributed to research in topics: Data acquisition & Microscope. The author has an hindex of 18, co-authored 23 publications receiving 3168 citations. Previous affiliations of James Pulokas include University of Illinois at Urbana–Champaign.

Papers
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Journal ArticleDOI
TL;DR: The primary automated data acquisition software system, Leginon, has been completely redesigned over the past two years and the system has demonstrated the capacity for high throughput data acquisition by acquiring images of more than 100,000 particles in a single session at the microscope.

1,505 citations

Journal ArticleDOI
TL;DR: The vision for this technique is to provide a straightforward manner in which users can proceed from raw data to a reliable 3D reconstruction through a pipeline that both facilitates management of the processing steps and makes the results at each step more transparent.

858 citations

Journal ArticleDOI
TL;DR: A system to automatically acquire cryo-electron micrographs is developed designed to emulate all of the decisions and actions of a highly trained microscopist in collecting data from a vitreous ice specimen.

322 citations

Journal ArticleDOI
TL;DR: How UCSF Tomo was integrated into Leginon, what users must do to set up a data collection session, how the automatic collection proceeds, how archived data about the process can be accessed and used, and how the software has been tested are described.

181 citations

Journal ArticleDOI
TL;DR: A system to automatically acquire large numbers of acceptable quality images from specimens of negatively stained catalase, a biological protein which forms crystals, and the performance of the system as compared to a human operator is described.

154 citations


Cited by
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Journal ArticleDOI
13 Mar 2020-Science
TL;DR: The authors show that this protein binds at least 10 times more tightly than the corresponding spike protein of severe acute respiratory syndrome (SARS)–CoV to their common host cell receptor, and test several published SARS-CoV RBD-specific monoclonal antibodies found that they do not have appreciable binding to 2019-nCoV S, suggesting that antibody cross-reactivity may be limited between the two RBDs.
Abstract: The outbreak of a novel coronavirus (2019-nCoV) represents a pandemic threat that has been declared a public health emergency of international concern. The CoV spike (S) glycoprotein is a key target for vaccines, therapeutic antibodies, and diagnostics. To facilitate medical countermeasure development, we determined a 3.5-angstrom-resolution cryo-electron microscopy structure of the 2019-nCoV S trimer in the prefusion conformation. The predominant state of the trimer has one of the three receptor-binding domains (RBDs) rotated up in a receptor-accessible conformation. We also provide biophysical and structural evidence that the 2019-nCoV S protein binds angiotensin-converting enzyme 2 (ACE2) with higher affinity than does severe acute respiratory syndrome (SARS)-CoV S. Additionally, we tested several published SARS-CoV RBD-specific monoclonal antibodies and found that they do not have appreciable binding to 2019-nCoV S, suggesting that antibody cross-reactivity may be limited between the two RBDs. The structure of 2019-nCoV S should enable the rapid development and evaluation of medical countermeasures to address the ongoing public health crisis.

7,324 citations

Journal ArticleDOI
16 Apr 2020-Cell
TL;DR: It is demonstrating that cross-neutralizing antibodies targeting conserved S epitopes can be elicited upon vaccination, and it is shown that SARS-CoV-2 S uses ACE2 to enter cells and that the receptor-binding domains of Sars- coV- 2 S and SARS S bind with similar affinities to human ACE2, correlating with the efficient spread of SATS among humans.

7,219 citations

Journal ArticleDOI
TL;DR: Probing the various interfaces of nanoparticle/biological interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings.
Abstract: Rapid growth in nanotechnology is increasing the likelihood of engineered nanomaterials coming into contact with humans and the environment. Nanoparticles interacting with proteins, membranes, cells, DNA and organelles establish a series of nanoparticle/biological interfaces that depend on colloidal forces as well as dynamic biophysicochemical interactions. These interactions lead to the formation of protein coronas, particle wrapping, intracellular uptake and biocatalytic processes that could have biocompatible or bioadverse outcomes. For their part, the biomolecules may induce phase transformations, free energy releases, restructuring and dissolution at the nanomaterial surface. Probing these various interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings. This knowledge is important from the perspective of safe use of nanomaterials.

6,075 citations

Journal ArticleDOI
TL;DR: Developments that reduce the computational costs of the underlying maximum a posteriori (MAP) algorithm, as well as statistical considerations that yield new insights into the accuracy with which the relative orientations of individual particles may be determined are described.

4,554 citations

Journal ArticleDOI
09 Nov 2018-eLife
TL;DR: CPU-based vector acceleration has been added in addition to GPU support, which provides flexibility in use of resources and avoids memory limitations in the third major release of RELION.
Abstract: Here, we describe the third major release of RELION. CPU-based vector acceleration has been added in addition to GPU support, which provides flexibility in use of resources and avoids memory limitations. Reference-free autopicking with Laplacian-of-Gaussian filtering and execution of jobs from python allows non-interactive processing during acquisition, including 2D-classification, de novo model generation and 3D-classification. Per-particle refinement of CTF parameters and correction of estimated beam tilt provides higher resolution reconstructions when particles are at different heights in the ice, and/or coma-free alignment has not been optimal. Ewald sphere curvature correction improves resolution for large particles. We illustrate these developments with publicly available data sets: together with a Bayesian approach to beam-induced motion correction it leads to resolution improvements of 0.2-0.7 A compared to previous RELION versions.

3,520 citations