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…
Molecular architecture and conservation of an immature human endogenous retrovirus The human endogenous retrovirus K (HERV-K) is the most recently acquired endogenous retrovirus in the human genome and is activated and expressed in many cancers and amyotrophic lateral sclerosis. We present the immature HERV-K capsid structure at 3.2 Å resolution determined from native virus-like particles using cryo-electron tomography and subtomogram…
Structural basis for breadth development in the HIV-1 V3-glycan targeting DH270 antibody clonal lineage Antibody affinity maturation enables adaptive immune responses to a wide range of pathogens. In some individuals broadly neutralizing antibodies develop to recognize rapidly mutating pathogens with extensive sequence diversity. Vaccine design for pathogens such as HIV-1 and influenza has therefore focused on recapitulating the natural…
Structure and dynamics of the Arabidopsis O-fucosyltransferase SPINDLY SPINDLY (SPY) in Arabidopsis thaliana is a novel nucleocytoplasmic protein O-fucosyltransferase (POFUT), which regulates diverse developmental processes. Sequence analysis indicates that SPY is distinct from ER-localized POFUTs and contains N-terminal tetratricopeptide repeats (TPRs) and a C-terminal catalytic domain resembling the O-linked-N-acetylglucosamine (GlcNAc) transferases (OGTs). However, the structural feature that determines the…
Redox-sensitive E2 Rad6 controls cellular response to oxidative stress via K63-linked ubiquitination of ribosomes In this study, we set out to investigate the key role of Rad6 in regulating cellular response to stress in budding yeast as part of the RTU. Rad6 is small (20 kDa), highly conserved, and a multifunctional E2 involved in DNA repair and in the…
Structural basis of NPR1 in activating plant immunity We report cryo-electron microscopy and crystal structures of Arabidopsis NPR1 and its complex with the transcription factor TGA3. Cryo-electron microscopy analysis reveals that NPR1 is a bird-shaped homodimer comprising a central Broad-complex, Tramtrack and Bric-à-brac (BTB) domain, a BTB and carboxyterminal Kelch helix bundle, four ankyrin repeats and a disordered salicylic-acid-binding…
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…
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…
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…
Single-particle cryo-EM structure of a voltage-activated potassium channel in lipid nanodiscs The structure of a voltage-activated potassium channel in lipid nanodiscs solved using cryo-electron microscopy is similar to previous X-ray structures, and provides insights into the mechanism of C-type inactivation. eLife, 7:e37558, 2018.
Cryo-EM structure of human rhodopsin bound to an inhibitory G protein For the first time, scientists have visualized the interaction between two critical components of the body’s vast cellular communication network, a discovery that could lead to more effective medications with fewer side effects for conditions ranging from migraine to cancer. The near-atomic resolution images obtained, show a G-protein coupled…
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 -galactosidase, and derivation of atom-specific measures of local flexibility of the bound inhibitor using constrained molecular dynamics simulations. Structure, 26(6), p. 848-85, 2018.
Cryo-EM Structures Reveal Mechanism and Inhibition of DNA Targeting by a CRISPR-Cas Surveillance Complex Electron-microscopy images reveal how a CRISPR system marks specific DNA sequences for destruction. Microbes use CRISPR as a defense system to fend off viruses and other invaders, and geneticists have harnessed it to alter DNA sequences in a process called gene editing. We used cryo-electron microscopy…
