Although viruses are extremely diverse in shape and size, evolution has led to a limited number of viral classes or lineages, which is probably linked to the assembly constraints of a viable capsid. Viral assembly mechanisms are restricted to two general pathways, (i) co-assembly of capsid proteins and single-stranded nucleic acids and (ii) a sequential mechanism in which scaffolding-mediated capsid precursor assembly is followed by genome packaging. Cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), which are revolutionizing structural biology, are central to determining the high-resolution structures of many viral assemblies as well as those of assembly intermediates. This wealth of cryo-EM data has also led to the development and redesign of virus-based platforms for biomedical and biotechnological applications. In this Review, we will discuss recent viral assembly analyses by cryo-EM and cryo-ET showing how natural assembly mechanisms are used to encapsulate heterologous cargos including chemicals, enzymes, and/or nucleic acids for a variety of nanotechnological applications.
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http://dx.doi.org/10.1038/s41589-020-0477-1 | DOI Listing |
Protein Sci
February 2025
Department of Chemistry, Institute of Biochemistry, BOKU University, Vienna, Austria.
Prokaryotic heme biosynthesis in Gram-positive bacteria follows the coproporphyrin-dependent heme biosynthesis pathway. The last step in this pathway is catalyzed by the enzyme coproheme decarboxylase, which oxidatively transforms two propionate groups into vinyl groups yielding heme b. The catalytic reaction cycle of coproheme decarboxylases exhibits four different states: the apo-form, the substrate (coproheme)-bound form, a transient three-propionate intermediate form (monovinyl, monopropionate deuteroheme; MMD), and the product (heme b)-bound form.
View Article and Find Full Text PDFProtein Sci
February 2025
Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
Polymyxins are last-resort antimicrobial peptides administered clinically against multi-drug resistant bacteria, specifically in the case of Gram-negative species. However, an increasing number of these pathogens employ a defense strategy that involves a relay of enzymes encoded by the pmrE (ugd) loci and the arnBCDTEF operon. The pathway modifies the lipid-A component of the outer membrane (OM) lipopolysaccharide (LPS) by adding a 4-amino-4-deoxy-l-arabinose (L-Ara4N) headgroup, which renders polymyxins ineffective.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Chemistry, School of Science, Westlake University, Hangzhou, Zhejiang Province, China.
The self-assembly of small molecules through non-covalent interactions is an emerging and promising strategy for building dynamic, stable, and large-scale structures. One remaining challenge is making the non-covalent interactions occur in the ideal positions to generate strength comparable to that of covalent bonds. This work shows that small molecule YAWF can self-assemble into a liquid-crystal hydrogel (LCH), the mechanical properties of which could be controlled by water.
View Article and Find Full Text PDFCurr Opin Struct Biol
January 2025
Department of Computer Science, Purdue University, West Lafayette, IN, USA; Department of Biological Sciences, Purdue University, West Lafayette, IN, USA. Electronic address:
Cryo-electron microscopy (Cryo-EM) has revolutionized structural biology by enabling the determination of macromolecular structures that were challenging to study with conventional methods. Processing cryo-EM data involves several computational steps to derive three-dimensional structures from raw projections. Recent advancements in artificial intelligence (AI) including deep learning have significantly improved the performance of these processes.
View Article and Find Full Text PDFCell Rep
January 2025
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA. Electronic address:
One of the striking features of human immunodeficiency virus (HIV) is the capsid, a fullerene cone comprised of pleomorphic capsid protein (CA) that shields the viral genome and recruits cofactors. Despite significant advances in understanding the mechanisms of HIV-1 CA assembly and host factor interactions, HIV-2 CA assembly remains poorly understood. By templating the assembly of HIV-2 CA on functionalized liposomes, we report high-resolution structures of the HIV-2 CA lattice, including both CA hexamers and pentamers, alone and with peptides of host phenylalanine-glycine (FG)-motif proteins Nup153 and CPSF6.
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