High-resolution Cryo-EM Analysis of the Therapeutic Pseudomonas Phage Pa223.

Cryogenic electron microscopy (cryo-EM) analysis of bacteriophages is a valuable method for deciphering virus composition and conformational plasticity. In this study, we present a high-resolution structural atlas of the Pseudomonas virus Pa223, a phage from the Bruynoghevirus genus that has recently been used in clinical cocktails for treating cystic fibrosis and non-cystic fibrosis bronchiectasis, as well as for compassionate care. By combining bioinformatics, proteomics, cryo-EM single particle analysis, and localized reconstruction, we annotated and built atomic models for eight structural polypeptide chains that form the icosahedral capsid and noncontractile tail.

High-resolution cryo-EM analysis of the therapeutic phage Pa223.

Unlabelled: Cryogenic electron microscopy (cryo-EM) analysis of bacteriophages is a valuable method for deciphering virus composition and conformational plasticity. In this study, we present a high-resolution structural atlas of the virus Pa223, a phage from the genus that has recently been used in clinical cocktails for treating cystic fibrosis and non-cystic fibrosis bronchiectasis, as well as for compassionate care. By combining bioinformatics, proteomics, cryo-EM single particle analysis, and localized reconstruction, we annotated and built atomic models for eight structural polypeptide chains that form the icosahedral capsid and noncontractile tail.

RAN MODULATES ALLOSTERIC CROSSTALK BETWEEN IMPORTIN β SURFACES.

A cellular gradient of the GTPase Ran orchestrates the movement of import and export complexes through the Nuclear Pore Complex (NPC). Ran-GTP modulates two essential activities of importin β for nuclear import. On one hand, it reduces the avidity of importin β for phenylalanine-glycine-rich nucleoporins (FG-nups), facilitating the passage of import complexes through the permeability barrier; on the other hand, it disassembles import complexes, releasing the import cargo into the nucleus.

Cryo-EM analysis of Pseudomonas phage Pa193 structural components.

The World Health Organization has designated Pseudomonas aeruginosa as a critical pathogen for the development of new antimicrobials. Bacterial viruses, or bacteriophages, have been used in various clinical settings, commonly called phage therapy, to address this growing public health crisis. Here, we describe a high-resolution structural atlas of a therapeutic, contractile-tailed Pseudomonas phage, Pa193.

Integrative structural analysis of Pseudomonas phage DEV reveals a genome ejection motor.

DEV is an obligatory lytic Pseudomonas phage of the N4-like genus, recently reclassified as Schitoviridae. The DEV genome encodes 91 ORFs, including a 3398 amino acid virion-associated RNA polymerase (vRNAP). Here, we describe the complete architecture of DEV, determined using a combination of cryo-electron microscopy localized reconstruction, biochemical methods, and genetic knockouts.

Structural basis for nuclear import of hepatitis B virus (HBV) nucleocapsid core.

Nuclear import of the hepatitis B virus (HBV) nucleocapsid is essential for replication that occurs in the nucleus. The ~360-angstrom HBV capsid translocates to the nuclear pore complex (NPC) as an intact particle, hijacking human importins in a reaction stimulated by host kinases. This paper describes the mechanisms of HBV capsid recognition by importins.

Use of Localized Reconstruction to Visualize the Shigella Phage Sf6 Tail Apparatus.

Cryogenic electron microscopy (cryo-EM) single-particle analysis has revolutionized the structural analysis of icosahedral viruses, including tailed bacteriophages. In recent years, localized (or focused) reconstruction has emerged as a powerful data analysis method to capture symmetry mismatches and resolve asymmetric features in icosahedral viruses. Here, we describe the methods used to reconstruct the 2.

High-resolution cryo-EM structure of the Pseudomonas bacteriophage E217.

E217 is a Pseudomonas phage used in an experimental cocktail to eradicate cystic fibrosis-associated Pseudomonas aeruginosa. Here, we describe the structure of the whole E217 virion before and after DNA ejection at 3.1 Å and 4.

High-resolution cryo-EM structure of the virus Sf6 genome delivery tail machine.

Sf6 is a bacterial virus that infects the human pathogen Here, we describe the cryo-electron microscopy structure of the Sf6 tail machine before DNA ejection, which we determined at a 2.7-angstrom resolution. We built de novo structures of all tail components and resolved four symmetry-mismatched interfaces.

Viral Small Terminase: A Divergent Structural Framework for a Conserved Biological Function.

The genome packaging motor of bacteriophages and herpesviruses is built by two terminase subunits, known as large (TerL) and small (TerS), both essential for viral genome packaging. TerL structure, composition, and assembly to an empty capsid, as well as the mechanisms of ATP-dependent DNA packaging, have been studied in depth, shedding light on the chemo-mechanical coupling between ATP hydrolysis and DNA translocation. Instead, significantly less is known about the small terminase subunit, TerS, which is dispensable or even inhibitory in vitro, but essential in vivo.

Terminase Subunits from the Pseudomonas-Phage E217.

Pseudomonas phages are increasingly important biomedicines for phage therapy, but little is known about how these viruses package DNA. This paper explores the terminase subunits from the Myoviridae E217, a Pseudomonas-phage used in an experimental cocktail to eradicate P. aeruginosa in vitro and in animal models.

Viral Ejection Proteins: Mosaically Conserved, Conformational Gymnasts.

Bacterial viruses (or bacteriophages) have developed formidable ways to deliver their genetic information inside bacteria, overcoming the complexity of the bacterial-cell envelope. In short-tailed phages of the superfamily, genome ejection is mediated by a set of mysterious internal virion proteins, also called ejection or pilot proteins, which are required for infectivity. The ejection proteins are challenging to study due to their plastic structures and transient assembly and have remained less characterized than classical components such as the phage coat protein or terminase subunit.

Cryo-EM structure of the periplasmic tunnel of T7 DNA-ejectosome at 2.7 Å resolution.

Hershey and Chase used bacteriophage T2 genome delivery inside Escherichia coli to demonstrate that DNA, not protein, is the genetic material. Seventy years later, our understanding of viral genome delivery in prokaryotes remains limited, especially for short-tailed phages of the Podoviridae family. These viruses expel mysterious ejection proteins found inside the capsid to form a DNA-ejectosome for genome delivery into bacteria.

Metal-Binding Q-Proline Macrocycles.

We introduce the efficient Fmoc-SPPS and peptoid synthesis of Q-proline-based, metal-binding macrocycles (QPMs), which bind metal cations and display nine functional groups. Metal-free QPMs are disordered, evidenced by NMR and a crystal structure of QPM- obtained through racemic crystallization. Upon addition of metal cations, QPMs adopt ordered structures.

Solution structure, glycan specificity and of phenol oxidase inhibitory activity of Anopheles C-type lectins CTL4 and CTLMA2.

Malaria, the world's most devastating parasitic disease, is transmitted between humans by mosquitoes of the Anopheles genus. An. gambiae is the principal malaria vector in Sub-Saharan Africa.

Anopheles gambiae TEP1 forms a complex with the coiled-coil domain of LRIM1/APL1C following a conformational change in the thioester domain.

The complement-like protein thioester-containing protein 1 (TEP1) is a key factor in the immune response of the malaria vector Anopheles gambiae to pathogens. Multiple allelic variants of TEP1 have been identified in laboratory strains and in the field, and are correlated with distinct immunophenotypes. TEP1 is tightly regulated by conformational changes induced by cleavage in a protease-sensitive region.

Insights into an evolutionary strategy leading to antibiotic resistance.

Metallo-β-lactamases (MBLs) with activity towards a broad-spectrum of β-lactam antibiotics have become a major threat to public health, not least due to their ability to rapidly adapt their substrate preference. In this study, the capability of the MBL AIM-1 to evade antibiotic pressure by introducing specific mutations was probed by two alternative methods, i.e.

Discovery of a PCAF Bromodomain Chemical Probe.

The p300/CBP-associated factor (PCAF) and related GCN5 bromodomain-containing lysine acetyl transferases are members of subfamily I of the bromodomain phylogenetic tree. Iterative cycles of rational inhibitor design and biophysical characterization led to the discovery of the triazolopthalazine-based L-45 (dubbed L-Moses) as the first potent, selective, and cell-active PCAF bromodomain (Brd) inhibitor. Synthesis from readily available (1R,2S)-(-)-norephedrine furnished L-45 in enantiopure form.