A molecular switch modulates assembly and host factor binding of the HIV-1 capsid.
Schirra, R.T., Dos Santos, N.F.B., Zadrozny, K.K., Kucharska, I., Ganser-Pornillos, B.K., Pornillos, O.(2023) Nat Struct Mol Biol 30: 383-390
- PubMed: 36759579 
- DOI: https://doi.org/10.1038/s41594-022-00913-5
- Primary Citation of Related Structures:  
7URN, 7URT, 8EEP, 8EET, 8EJL - PubMed Abstract: 
The HIV-1 capsid is a fullerene cone made of quasi-equivalent hexamers and pentamers of the viral CA protein. Typically, quasi-equivalent assembly of viral capsid subunits is controlled by a molecular switch. Here, we identify a Thr-Val-Gly-Gly motif that modulates CA hexamer/pentamer switching by folding into a 3 10 helix in the pentamer and random coil in the hexamer. Manipulating the coil/helix configuration of the motif allowed us to control pentamer and hexamer formation in a predictable manner, thus proving its function as a molecular switch. Importantly, the switch also remodels the common binding site for host factors that are critical for viral replication and the new ultra-potent HIV-1 inhibitor lenacapavir. This study reveals that a critical assembly element also modulates the post-assembly and viral replication functions of the HIV-1 capsid and provides new insights on capsid function and inhibition.
Organizational Affiliation: 
Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.