Abstract
APOBEC3G (A3G) is a cellular protein that inhibits HIV-1 infection through virion incorporation. The interaction of the A3G N-terminal domain (NTD) with RNA is essential for A3G incorporation in the HIV-1 virion. The interaction between A3G-NTD and RNA is not completely understood. The A3G-NTD is also recognized by HIV-1 Viral infectivity factor (Vif) and A3G-Vif binding leads to A3G degradation. Therefore, the A3G-Vif interaction is a target for the development of antiviral therapies that block HIV-1 replication. However, targeting the A3G-Vif interactions could disrupt the A3G-RNA interactions that are required for A3G's antiviral activity. To better understand A3G-RNA binding, we generated in silico docking models to simulate the RNA-binding propensity of A3G-NTD. We simulated the A3G-NTD residues with high RNA-binding propensity, experimentally validated our prediction by testing A3G-NTD mutations, and identified structural determinants of A3G-RNA binding. In addition, we found a novel amino acid residue, I26 responsible for RNA interaction. The new structural insights provided here will facilitate the design of pharmaceuticals that inhibit A3G-Vif interactions without negatively impacting A3G-RNA interactions.
Highlights
APOBEC3G (A3G), a member of the cellular cytidine deaminase APOBEC3 superfamily, exhibits anti-HIV activity primarily by inducing G-to-A hypermutation in the viral cDNA (Wedekind et al, 2003; Conticello et al, 2007; Conticello, 2008; Desimmie et al, 2016)
The aaRNA predictor can generate accurate and robust RNA binding propensities (BP) for each residue based on both sequence and structure features, and is suitable for studying proteins like A3G that have flexible potential binding loops to interact with RNA (Supplementary Figure 1)
Because the Viral infectivity factor (Vif) binding region partially overlaps with the RNA interaction domain of A3G-N-terminal domain (NTD), we further investigated the sensitivity of the R122A mutant toward Vif-mediated degradation
Summary
APOBEC3G (A3G), a member of the cellular cytidine deaminase APOBEC3 superfamily, exhibits anti-HIV activity primarily by inducing G-to-A hypermutation in the viral cDNA (Wedekind et al, 2003; Conticello et al, 2007; Conticello, 2008; Desimmie et al, 2016). The N-terminal domain (A3G-NTD), consisting of residues 1-200, is catalytically inactive but indispensable for Vif-interaction and A3G encapsidation (Bogerd et al, 2004; Mangeat et al, 2004; Schrofelbauer et al, 2004; Xu et al, 2004; Navarro et al, 2005; Iwatani et al, 2006; Huthoff and Malim, 2007; Izumi et al, 2010; Feng and Chelico, 2011; Bélanger and Langlois, 2015) and is involved in the association with viral and cellular RNAs (Wang et al, 2007; Bach et al, 2008; Bulliard et al, 2009; Friew et al, 2009; Huthoff et al, 2009; Chelico et al, 2010; Lavens et al, 2010; Zhang et al, 2010; Shlyakhtenko et al, 2011; Uyttendaele et al, 2012; Apolonia et al, 2015; Bélanger and Langlois, 2015). Two tryptophan residues at position 94 and 127, and residues R24, S28, R30, R122, Y124, and F126 have been determined to be involved in A3G-RNA interactions (Table 1) (Huthoff and Malim, 2007; Bach et al, 2008; Bulliard et al, 2009; Huthoff et al, 2009; Zhang et al, 2010; Bélanger and Langlois, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
