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1. Full scale structural, mechanical and dynamical properties of HIV-1 liposomes

   https://doi.org/10.1371/journal.pcbi.1009781  

   Bryer, Alexander J.; Reddy, Tyler; Lyman, Edward; Perilla, Juan R. (January 2022, PLOS Computational Biology)

   Schlessinger, Avner (Ed.)

   Enveloped viruses are enclosed by a lipid membrane inside of which are all of the components necessary for the virus life cycle; viral proteins, the viral genome and metabolites. Viral envelopes are lipid bilayers that adopt morphologies ranging from spheres to tubes. The envelope is derived from the host cell during viral replication. Thus, the composition of the bilayer depends on the complex constitution of lipids from the host-cell’s organelle(s) where assembly and/or budding of the viral particle occurs. Here, molecular dynamics (MD) simulations of authentic, asymmetric HIV-1 liposomes are used to derive a unique level of resolution of its full-scale structure, mechanics and dynamics. Analysis of the structural properties reveal the distribution of thicknesses of the bilayers over the entire liposome as well as its global fluctuations. Moreover, full-scale mechanical analyses are employed to derive the global bending rigidity of HIV-1 liposomes. Finally, dynamical properties of the lipid molecules reveal important relationships between their 3D diffusion, the location of lipid-rafts and the asymmetrical composition of the envelope. Overall, our simulations reveal complex relationships between the rich lipid composition of the HIV-1 liposome and its structural, mechanical and dynamical properties with critical consequences to different stages of HIV-1’s life cycle. 

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2. Influenza hemagglutinin drives viral entry via two sequential intramembrane mechanisms

   https://doi.org/10.1073/pnas.1914188117  

   Pabis, Anna; Rawle, Robert J.; Kasson, Peter M. (March 2020, Proceedings of the National Academy of Sciences)

   Enveloped viruses enter cells via a process of membrane fusion between the viral envelope and a cellular membrane. For influenza virus, mutational data have shown that the membrane-inserted portions of the hemagglutinin protein play a critical role in achieving fusion. In contrast to the relatively well-understood ectodomain, a predictive mechanistic understanding of the intramembrane mechanisms by which influenza hemagglutinin drives fusion has been elusive. We used molecular dynamics simulations of fusion between a full-length hemagglutinin proteoliposome and a lipid bilayer to analyze these mechanisms. In our simulations, hemagglutinin first acts within the membrane to increase lipid tail protrusion and promote stalk formation and then acts to engage the distal leaflets of each membrane and promote stalk widening, curvature, and eventual fusion. These two sequential mechanisms, one occurring before stalk formation and one after, are consistent with our experimental measurements of single-virus fusion kinetics to liposomes of different sizes. The resulting model also helps explain and integrate previous mutational and biophysical data, particularly the mutational sensitivity of the fusion peptide N terminus and the length sensitivity of the transmembrane domain. We hypothesize that entry by other enveloped viruses may also use sequential processes of acyl tail exposure, followed by membrane curvature and distal leaflet engagement. 

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3. Oxidative degradation of sequence-defined peptoid oligomers

   https://doi.org/10.1039/D2ME00179A  

   Schunk, Hattie C.; Austin, Mariah J.; Taha, Bradley Z.; McClellan, Matthew S.; Suggs, Laura J.; Rosales, Adrianne M. (January 2023, Molecular Systems Design & Engineering)

   Due to their N -substitution, peptoids are generally regarded as resistant to biological degradation, such as enzymatic and hydrolytic mechanisms. This stability is an especially attractive feature for therapeutic development and is a selling point of many previous biological studies. However, another key mode of degradation remains to be fully explored, namely oxidative degradation mediated by reactive oxygen and nitrogen species (ROS/RNS). ROS and RNS are biologically relevant in numerous contexts where biomaterials may be present. Thus, improving understanding of peptoid oxidative susceptibility is crucial to exploit their full potential in the biomaterials field, where an oxidatively-labile but enzymatically stable molecule can offer attractive properties. Toward this end, we demonstrate a fundamental characterization of sequence-defined peptoid chains in the presence of chemically generated ROS, as compared to ROS-susceptible peptides such as proline and lysine oligomers. Lysine oligomers showed the fastest degradation rates to ROS and the enzyme trypsin. Peptoids degraded in metal catalyzed oxidation conditions at rates on par with poly(prolines), while maintaining resistance to enzymatic degradation. Furthermore, lysine-containing peptide–peptoid hybrid molecules showed tunability in both ROS-mediated and enzyme-mediated degradation, with rates intermediate to lysine and peptoid oligomers. When lysine-mimetic side-chains were incorporated into a peptoid backbone, the rate of degradation matched that of the lysine peptide oligomers, but remained resistant to enzymatic degradation. These results expand understanding of peptoid degradation to oxidative and enzymatic mechanisms, and demonstrate the potential for peptoid incorporation into materials where selectivity towards oxidative degradation is necessary, or directed enzymatic susceptibility is desired. 

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4. Intracellular interactions shape antiviral resistance outcomes in poliovirus via eco-evolutionary feedback

   https://doi.org/10.1038/s41559-025-02926-x  

   Robertson, Alexander J; Kerr, Benjamin; Feder, Alison F (December 2025, Nature Ecology & Evolution)

   Resistance evolution can undermine antiviral treatment. However, targeting antivirals to shared viral proteins could inhibit resistance evolution if susceptible viruses sensitize resistant ones during cellular coinfection. Pocapavir, a poliovirus capsid inhibitor, uses this sociovirological interference strategy. While susceptible viruses substantially suppress pocapavir resistance in cell culture, a pocapavir clinical trial found widespread resistance and limited clearance time improvements in treated participants. Here, to reconcile these findings, we present an intrahost eco-evolutionary model of pocapavir-treated poliovirus, which reproduces both in vitro interference and clinical resistance evolution. In the short term, high densities of susceptible viruses sensitize resistant ones, mirroring cell culture results. However, over multiple replication cycles, pocapavir’s high potency collapses viral density, reducing coinfection and enabling resistance evolution, as observed clinically. Because resistance suppression relies on coinfection, enhancing susceptible virus survival could offer therapeutic advantages. Counterintuitively, we demonstrate that lessening antiviral potency can increase coinfection, limiting resistance while also maintaining low viral load. These findings suggest that antivirals relying on viral intracellular interactions must balance immediate neutralization with preserving future coinfection for sustained inhibition. Explicitly considering the eco-evolutionary feedback encompassing viral density, shared phenotypes and absolute fitness provides new insights for effective therapy design and illuminates viral evolutionary dynamics more broadly. 

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5. Biophysical Modeling of SARS-CoV-2 Assembly: Genome Condensation and Budding

   https://doi.org/10.3390/v14102089  

   Li, Siyu; Zandi, Roya (October 2022, Viruses)

   The COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spurred unprecedented and concerted worldwide research to curtail and eradicate this pathogen. SARS-CoV-2 has four structural proteins: Envelope (E), Membrane (M), Nucleocapsid (N), and Spike (S), which self-assemble along with its RNA into the infectious virus by budding from intracellular lipid membranes. In this paper, we develop a model to explore the mechanisms of RNA condensation by structural proteins, protein oligomerization and cellular membrane–protein interactions that control the budding process and the ultimate virus structure. Using molecular dynamics simulations, we have deciphered how the positively charged N proteins interact and condense the very long genomic RNA resulting in its packaging by a lipid envelope decorated with structural proteins inside a host cell. Furthermore, considering the length of RNA and the size of the virus, we find that the intrinsic curvature of M proteins is essential for virus budding. While most current research has focused on the S protein, which is responsible for viral entry, and it has been motivated by the need to develop efficacious vaccines, the development of resistance through mutations in this crucial protein makes it essential to elucidate the details of the viral life cycle to identify other drug targets for future therapy. Our simulations will provide insight into the viral life cycle through the assembly of viral particles de novo and potentially identify therapeutic targets for future drug development. 

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