Identification of the initial nucleocapsid recognition element in the HIV-1 RNA packaging signal
Loading...
Links to Files
Author/Creator ORCID
Date
2020-07-09
Type of Work
Department
Program
Citation of Original Publication
Ding, Pengfei; Kharytonchyk, Siarhei; Waller, Alexis; Mbaekwe, Ugonna; Basappa, Sapna; Kuo, Nansen; Frank, Heather M.; Quasney, Christina; Kidane, Aaron; Swanson, Canessa; Van, Verna; Sarkar, Mitali; Cannistraci, Emily; Chaudhary, Ridhi; Flores, Hana; Telesnitsky, Alice; Summers, Michael F.; Identification of the initial nucleocapsid recognition element in the HIV-1 RNA packaging signal; PNAS July 28, 2020 117 (30) 17737-17746; https://www.pnas.org/content/117/30/17737
Rights
This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
Attribution 4.0 International (CC BY 4.0)
Attribution 4.0 International (CC BY 4.0)
Subjects
Abstract
Selective packaging of the HIV-1 genome during virus assembly is mediated by interactions between the dimeric 5ʹ-leader of the unspliced viral RNA and the nucleocapsid (NC) domains of a small number of assembling viral Gag polyproteins. Here, we show that the dimeric 5′-leader contains more than two dozen NC binding sites with affinities ranging from 40 nM to 1.4 μM, and that all high-affinity sites (Kd ≲ 400 nM) reside within a ∼150-nt region of the leader sufficient to promote RNA packaging (core encapsidation signal, ΨCES). The four initial binding sites with highest affinity reside near two symmetrically equivalent three-way junction structures. Unlike the other high-affinity sites, which bind NC with exothermic energetics, binding to these sites occurs endothermically due to concomitant unwinding of a weakly base-paired [UUUU]:[GGAG] helical element. Mutations that stabilize base pairing within this element eliminate NC binding to this site and severely impair RNA packaging into virus-like particles. NMR studies reveal that a recently discovered small-molecule inhibitor of HIV-1 RNA packaging that appears to function by stabilizing the structure of the leader binds directly to the [UUUU]:[GGAG] helix. Our findings suggest a sequential NC binding mechanism for Gag-genome assembly and identify a potential RNA Achilles’ heel to which HIV therapeutics may be targeted.