The mammalian two-hybrid system MAPPIT allows the detection of protein-protein interactions in intact human cells. We developed a random mutagenesis screening strategy based on MAPPIT to detect mutations that disrupt the interaction of one protein with multiple protein interactors simultaneously. The strategy was used to detect residues of the human cytidine deaminase Apobec3G that are importan...

APOBEC3G is a DNA cytidine deaminase that has antiviral activity against HIV-1 and other pathogenic viruses. In this study the crystal structure of the catalytically active C-terminal domain was determined to 2.25 A. This structure corroborates features previously observed in nuclear magnetic resonance (NMR) studies, a bulge in the second beta strand and a lengthening of the second alpha helix....

The human APOBEC3 proteins are a family of DNA-editing enzymes that play an important role in the innate immune response against retroviruses and retrotransposons. APOBEC3G is a member of this family that inhibits HIV-1 replication in the absence of the viral infectivity factor Vif. Inhibition of HIV replication occurs by both deamination of viral single-stranded DNA and a deamination-independe...

The antiretroviral activity of the cellular enzyme APOBEC3G has been attributed to the excessive deamination of cytidine (C) to uridine (U) in minus strand reverse transcripts, a process resulting in guanosine (G) to adenosine (A) hypermutation of plus strand DNAs. The HIV-1 Vif protein counteracts APOBEC3G by inducing proteasomal degradation and exclusion from virions through recruitment of a ...

HIV-1 and other retroviruses occasionally undergo hypermutation, characterized by a high rate of G-to-A substitution. Recently, the human apolipoprotein B mRNA-editing, enzyme-catalytic, polypeptide-like 3G (APOBEC3G), first identified as CEM15, was shown to be packaged into retroviral virions and to deaminate deoxycytidine to deoxyuridine in newly synthesized viral minus-strand DNA, thereby in...

Human cells harbor a variety of factors that function to block the proliferation of foreign nucleic acid. The APOBEC3G enzyme inhibits the replication of retroviruses by deaminating nascent retroviral cDNA cytosines to uracils, lesions that can result in lethal levels of hypermutation. Here, we demonstrate that APOBEC3G is capable of deaminating genomic cytosines in Saccharomyces cerevisiae. AP...

Human APOBEC3G exhibits anti-human immunodeficiency virus-1 (HIV-1) activity by deaminating cytidines of the minus strand of HIV-1. Here, we report a solution structure of the C-terminal deaminase domain of wild-type APOBEC3G. The interaction with DNA was examined. Many differences in the interaction were found between the wild type and recently studied mutant APOBEC3Gs. The position of the sub...

UNLABELLED HIV-1 is characterized by high genetic heterogeneity which is a challenge for developing therapeutics. Therefore, it is necessary to understand the extent of genetic variations that HIV is undergoing in North India. The objective of this study was to determine the role of genetic and functional role of Vif on APOBEC3G degradation. Vif is an accessory protein involved in counteracting...

APOBEC3G is the best known of several DNA cytosine deaminases that function to inhibit the replication of parasitic genetic elements including the lentivirus HIV. Several high-resolution structures of the APOBEC3G catalytic domain have been generated, but none reveal how this enzyme binds to substrate single-stranded DNA. Here, we constructed a panel of APOBEC3G amino acid substitution mutants ...

Activation-induced cytidine deaminase (AID) and APOBEC3G catalyze deamination of cytosine to uracil on single-stranded DNA, thereby setting in motion a regulated hypermutagenic process essential for human well-being. However, if regulation fails, havoc ensues. AID plays a central role in the synthesis of high affinity antibodies, and APOBEC3G inactivates human immunodeficiency virus-1. This min...