Structural highlightsFunctionABC3G_HUMAN DNA deaminase (cytidine deaminase) that mediates a form of innate resistance to retroviral infections (at least to HIV-1 infection) by triggering G-to-A hypermutation in the newly synthesized viral DNA. The replacements C-to-U in the minus strand DNA of HIV-1 during reverse transcription, leads to G-to-A transitions in the plus strand. The inhibition of viral replication is either due to the degradation of the minus strand before its integration or to the lethality of the hypermutations. Modification of both DNA strands is not excluded. This antiviral activity is neutralized by the virion infectivity factor (VIF), that prevents the incorporation of APOBEC3G into progeny HIV-1 virions by both inhibiting its translation and/or by inducing its ubiquitination and subsequent degradation by the 26S proteasome. May also prevent the transposition of a subset of retroelements. Binds a variety of RNAs, but does not display detectable APOB, NF1 and NAT1 mRNA editing.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
Publication Abstract from PubMed
Great effort has been devoted to discovering the basis of A3G-Vif interaction, the key event of HIV's counteraction mechanism to evade antiviral innate immune response. Here we show reconstitution of the A3G-Vif complex and subsequent A3G ubiquitination in vitro and report the cryo-EM structure of the A3G-Vif complex at 2.8 A resolution using solubility-enhanced variants of A3G and Vif. We present an atomic model of the A3G-Vif interface, which assembles via known amino acid determinants. This assembly is not achieved by protein-protein interaction alone, but also involves RNA. The cryo-EM structure and in vitro ubiquitination assays identify an adenine/guanine base preference for the interaction and a unique Vif-ribose contact. This establishes the biological significance of an RNA ligand. Further assessment of interactions between A3G, Vif, and RNA ligands show that the A3G-Vif assembly and subsequent ubiquitination can be controlled by amino acid mutations at the interface or by polynucleotide modification, suggesting that a specific chemical moiety would be a promising pharmacophore to inhibit the A3G-Vif interaction.
Structural insights into RNA bridging between HIV-1 Vif and antiviral factor APOBEC3G.,Kouno T, Shibata S, Shigematsu M, Hyun J, Kim TG, Matsuo H, Wolf M Nat Commun. 2023 Jul 7;14(1):4037. doi: 10.1038/s41467-023-39796-5. PMID:37419875[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Chen KM, Harjes E, Gross PJ, Fahmy A, Lu Y, Shindo K, Harris RS, Matsuo H. Structure of the DNA deaminase domain of the HIV-1 restriction factor APOBEC3G. Nature. 2008 Mar 6;452(7183):116-9. Epub 2008 Feb 20. PMID:18288108 doi:10.1038/nature06638
- ↑ Kouno T, Shibata S, Shigematsu M, Hyun J, Kim TG, Matsuo H, Wolf M. Structural insights into RNA bridging between HIV-1 Vif and antiviral factor APOBEC3G. Nat Commun. 2023 Jul 7;14(1):4037. PMID:37419875 doi:10.1038/s41467-023-39796-5
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