8e40
From Proteopedia
Full-length APOBEC3G in complex with HIV-1 Vif, CBF-beta, and fork RNA
Structural highlights
FunctionABC3G_MACMU DNA deaminase (cytidine deaminase) which acts as an inhibitor of retrovirus replication and retrotransposon mobility via deaminase-dependent and -independent mechanisms. Exhibits antiviral activity against vif-deficient: HIV-1 and simian immunodeficiency viruses (SIVs). After the penetration of retroviral nucleocapsids into target cells of infection and the initiation of reverse transcription, it can induce the conversion of cytosine to uracil in the minus-sense single-strand viral DNA, leading to G-to-A hypermutations in the subsequent plus-strand viral DNA. The resultant detrimental levels of mutations in the proviral genome, along with a deamination-independent mechanism that works prior to the proviral integration, together exert efficient antiretroviral effects in infected target cells. Selectively targets single-stranded DNA and does not deaminate double-stranded DNA or single- or double-stranded RNA. May inhibit the mobility of LTR retrotransposons.[1] [2] Publication Abstract from PubMedHuman APOBEC3G (A3G) is a virus restriction factor that inhibits HIV-1 replication and triggers lethal hypermutation on viral reverse transcripts. HIV-1 viral infectivity factor (Vif) breaches this host A3G immunity by hijacking a cellular E3 ubiquitin ligase complex to target A3G for ubiquitination and degradation. The molecular mechanism of A3G targeting by Vif-E3 ligase is unknown, limiting the antiviral efforts targeting this host-pathogen interaction crucial for HIV-1 infection. Here, we report the cryo-electron microscopy structures of A3G bound to HIV-1 Vif in complex with T cell transcription cofactor CBF-beta and multiple components of the Cullin-5 RING E3 ubiquitin ligase. The structures reveal unexpected RNA-mediated interactions of Vif with A3G primarily through A3G's noncatalytic domain, while A3G's catalytic domain is poised for ubiquitin transfer. These structures elucidate the molecular mechanism by which HIV-1 Vif hijacks the host ubiquitin ligase to specifically target A3G to establish infection and offer structural information for the rational development of antiretroviral therapeutics. Structural basis for HIV-1 antagonism of host APOBEC3G via Cullin E3 ligase.,Ito F, Alvarez-Cabrera AL, Liu S, Yang H, Shiriaeva A, Zhou ZH, Chen XS Sci Adv. 2023 Jan 4;9(1):eade3168. doi: 10.1126/sciadv.ade3168. Epub 2023 Jan 4. PMID:36598981[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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