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…
Fab-dimerized glycan-reactive antibodies are a structural category of natural antibodies Natural antibodies (Abs) can target host glycans on the surface of pathogens. We studied the evolution of glycan-reactive B cells of rhesus macaques and humans using glycosylated HIV-1 envelope (Env) as a model antigen. We describe HIV-1 Env Fab-dimerized glycan (FDG)-reactive neutralizing Abs in HIV-1 vaccinated and simian-HIV (SHIV)-infected…
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…
Structural Basis for Virulence Activation of Francisella tularensis The bacterium Francisella tularensis (Ft) is one of the most infectious agents known. Ft virulence is controlled by a unique combination of transcription regulators: the MglA-SspA heterodimer, PigR, and the stress signal, ppGpp. MglA-SspA assembles with the σ70-associated RNAP holoenzyme (RNAPσ70), forming a virulence-specialized polymerase. These factors activate Francisella pathogenicity island…
Structural impact of K63 ubiquitin on yeast translocating ribosomes under oxidative stress K63 ubiquitination of ribosomes serves as a key regulator of protein production during cellular exposure to oxidative stress. Defining the structural and functional mechanisms of translation regulation would support the current understanding of critical reprogramming of eukaryotic gene expression. Our paper presents an examination of the structure…
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…
Disruption of the HIV-1 Envelope allosteric network blocks CD4-induced rearrangements The trimeric HIV-1 Envelope protein (Env) mediates viral-host cell fusion via a network of conformational transitions, with allosteric elements in each protomer orchestrating host receptor-induced exposure of the co-receptor binding site and fusion elements. To understand the molecular details of this allostery, here, we introduce Env mutations aimed to…
