First-ever biologically authentic computer model was completed of the HIV-1 virus liposome. Key finding from the simulations is the formation of sphingomyelin and cholesterol rich microdomains. HIV-1 is known to preferentially bud from regions of the host cell membrane where these constituents are in high abundance. Scientists are hopeful this basic research into viral envelopes can help efforts to develop new HIV-1 therapeutics, as well as laying a foundation for study of other enveloped viruses such as the novel coronavirus.

For the HIV-1 virus, a double layer of fatty molecules called lipids not only serves as its container, but also plays a key role in the virus’s replication and infectivity. Scientists have used supercomputers to complete the first-ever biologically authentic computer model of the HIV-1 virus liposome, its complete spherical lipid bilayer.

What’s more, this study comes fresh off the heels of a new atomistic model of the HIV-1 capsid, which contains its genetic material. The scientists are hopeful this basic research into viral envelopes can help efforts to develop new HIV-1 therapeutics, as well as laying a foundation for study of other enveloped viruses such as the novel coronavirus, SARS-CoV-2.

«This work represents an investigation of the HIV-1 liposome at full-scale, and with an unprecedented level of chemical complexity,» said Alex Bryer, a PhD student in the Perilla Laboratory, Department of Chemistry and Biochemistry, University of Delaware. Bryer is the lead author of the liposome-modeling research, published January 2022 in the journal PLOS Computational Biology.

The science team developed a complex chemical model of the HIV-1 liposome that revealed key characteristics of the liposome’s asymmetry. Most such models assume a geometrically uniform structure and don’t capture the asymmetry inherent in such biological containers.

Lipid Flip-Flop

Bryer and his co-authors investigated a mechanism that’s known colloquially as «lipid flip-flop,» which is when lipids in one of the leaflets of the bilayer are moved or transported to the other leaflet. The leaflets flip-flop the lipids and exchange the molecules for various purposes such as achieving a dynamic equilibrium.

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Materials provided by University of Texas at Austin, Texas Advanced Computing Center. Original written by Jorge Salazar. Note: Content may be edited for style and length.