Identification of the initial nucleocapsid recognition element in the HIV-1 RNA packaging signal.
Proc Natl Acad Sci U S A
; 117(30): 17737-17746, 2020 07 28.
Article
em En
| MEDLINE
| ID: mdl-32647061
ABSTRACT
Selective packaging of the HIV-1 genome during virus assembly is mediated by interactions between the dimeric 5'-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 â² 400 nM) reside within a â¼150-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.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA Viral
/
Infecções por HIV
/
HIV-1
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Montagem de Vírus
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Nucleocapsídeo
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Sequências Reguladoras de Ácido Ribonucleico
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2020
Tipo de documento:
Article