During HIV-1 assembly, the viral Gag polyprotein specifically selects the dimeric RNA genome for packaging into new virions. The 5' untranslated region (5'UTR) of the dimeric genome may adopt a conformation that is optimal for recognition by Gag. Further conformational rearrangement of the 5'UTR, promoted by the nucleocapsid (NC) domain of Gag, is predicted during virus maturation. Two 5'UTR dimer conformations, the kissing dimer (KD) and the extended dimer (ED), have been identified in vitro, which differ in the extent of intermolecular basepairing. Whether 5'UTRs from different HIV-1 strains with distinct sequences have access to the same dimer conformations has not been determined. Here, we applied fluorescence cross-correlation spectroscopy and single-molecule Förster resonance energy transfer imaging to demonstrate that 5'UTRs from two different HIV-1 subtypes form (KDs) with divergent stabilities. We further show that both 5'UTRs convert to a stable dimer in the presence of the viral NC protein, adopting a conformation consistent with extensive intermolecular contacts. These results support a unified model in which the genomes of diverse HIV-1 strains adopt an ED conformation.
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http://dx.doi.org/10.1016/j.bpj.2021.09.017 | DOI Listing |
Pathogens
December 2024
Laboratory of Macromolecular Structure, Department of Molecular Biology and Biochemistry, University of California Irvine, Steinhaus Hall, Irvine, CA 92697-3900, USA.
Concatemeric viral DNA is packaged into bacteriophage P22 procapsids via a headful packaging mechanism mediated by a molecular machine consisting of small (gp3) and large (gp2) terminase subunits. Although a negative stain reconstruction exists for the terminase holoenzyme, it is not clear how this complex binds the dodecameric portal protein located at a 5-fold mismatch vertex. Herein, we describe new assemblies for the holoenzyme.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
College of Polymer Science & Engineering, Sichuan University, Chengdu 610065, China. Electronic address:
While single-atom catalysts (SACs) have been extensively investigated as a high-atom-efficiency heterogeneous catalyst for peroxymonosulfate (PMS) oxidation reaction, the stable constructing and activation efficacy of the reaction sites remains less clarified. Herein, we employed gelatin as a N,O-bidentate ligand for Co (II) to form for a N-doped carbon precursor, while introducing NaCl as a template agent to induce the adoption of a Co-N conformation and disorganize the Co-O moiety. This approach facilitates uniform spatial isolation and atomic-level dispersion of Co atoms within the aerogel, effectively inhibiting the aggregation of Co during synthesis and enabling precise and controllable preparation of Co single-atom catalysts (SACs).
View Article and Find Full Text PDFIntrinsically disordered proteins or regions (IDPs or IDRs) exist as ensembles of conformations in the monomeric state and can adopt diverse binding modes, making their experimental and computational characterization challenging. Here, we developed Disobind, a deep-learning method that predicts inter-protein contact maps and interface residues for an IDR and a partner protein, leveraging sequence embeddings from a protein language model. Several current methods, in contrast, provide partner-independent predictions, require the structure of either protein, and/or are limited by the MSA quality.
View Article and Find Full Text PDFSci Rep
January 2025
Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, Poznan, 61 614, Poland.
The embellishing of the macrocycle core with sulfur substituents of varied sterical requirements changes the structural dynamics of chiral, triangular polyimines. Despite their formal high symmetry, these compounds adopt diverse conformations, in which the macrocycle core represents a non-changeable unit. DFT calculations reveal that the mutual arrangement of sulfur-containing substituents is controlled mainly by sterical interactions.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Shanghai Institute of Organic Chemistry, Materials Science, 345 lingling Road, 200032, Shanghai, CHINA.
Three-dimensional covalent organic frameworks (3D COFs), a class of highly porous crystalline polymers, have exhibited great potentials in many applications. However, the reported topologies of 3D COFs have been limited to high-symmetry crystal systems, which significantly hindered the development of such functional materials. Herein, we demonstrate the first construction of four highly crystalline orthorhombic 3D COFs with an unprecedented fmj topology, based on judiciously choosing rotatable monomers.
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