Inositol phosphates are assembly co-factors for HIV-1.Dick, R.A., Zadrozny, K.K., Xu, C., Schur, F.K.M., Lyddon, T.D., Ricana, C.L., Wagner, J.M., Perilla, J.R., Ganser-Pornillos, B.K., Johnson, M.C., Pornillos, O., Vogt, V.M.
(2018) Nature 560: 509-512
- PubMed: 30069050
- DOI: 10.1038/s41586-018-0396-4
- Structures With Same Primary Citation
- PubMed Abstract:
A short, 14-amino-acid segment called SP1, located in the Gag structural protein 1 , has a critical role during the formation of the HIV-1 virus particle. During virus assembly, the SP1 peptide and seven preceding residues fold into a six- ...
A short, 14-amino-acid segment called SP1, located in the Gag structural protein 1 , has a critical role during the formation of the HIV-1 virus particle. During virus assembly, the SP1 peptide and seven preceding residues fold into a six-helix bundle, which holds together the Gag hexamer and facilitates the formation of a curved immature hexagonal lattice underneath the viral membrane 2,3 . Upon completion of assembly and budding, proteolytic cleavage of Gag leads to virus maturation, in which the immature lattice is broken down; the liberated CA domain of Gag then re-assembles into the mature conical capsid that encloses the viral genome and associated enzymes. Folding and proteolysis of the six-helix bundle are crucial rate-limiting steps of both Gag assembly and disassembly, and the six-helix bundle is an established target of HIV-1 inhibitors 4,5 . Here, using a combination of structural and functional analyses, we show that inositol hexakisphosphate (InsP6, also known as IP 6 ) facilitates the formation of the six-helix bundle and assembly of the immature HIV-1 Gag lattice. IP 6 makes ionic contacts with two rings of lysine residues at the centre of the Gag hexamer. Proteolytic cleavage then unmasks an alternative binding site, where IP 6 interaction promotes the assembly of the mature capsid lattice. These studies identify IP 6 as a naturally occurring small molecule that promotes both assembly and maturation of HIV-1.
Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.