3v4k | pdb_00003v4k

First-In-Class Small Molecule Inhibitors of the Single-strand DNA Cytosine Deaminase APOBEC3G

spinqualitylabelsall models 3v4k, resolution 1.38Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3v4k is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, MG, ZN Related: 3v4j Gene: APOBEC3G, MDS019 (HUMAN) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ABC3G_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. Publication Abstract from PubMed APOBEC3G is a single-stranded DNA cytosine deaminase that comprises part of the innate immune response to viruses and transposons. Although APOBEC3G is the prototype for understanding the larger mammalian polynucleotide deaminase family, no specific chemical inhibitors exist to modulate its activity. High-throughput screening identified 34 compounds that inhibit APOBEC3G catalytic activity. Twenty of 34 small molecules contained catechol moieties, which are known to be sulfhydryl reactive following oxidation to the orthoquinone. Located proximal to the active site, C321 was identified as the binding site for the inhibitors by a combination of mutational screening, structural analysis, and mass spectrometry. Bulkier substitutions C321-to-L, F, Y, or W mimicked chemical inhibition. A strong specificity for APOBEC3G was evident, as most compounds failed to inhibit the related APOBEC3A enzyme or the unrelated enzymes E. coli uracil DNA glycosylase, HIV-1 RNase H, or HIV-1 integrase. Partial, but not complete, sensitivity could be conferred to APOBEC3A by introducing the entire C321 loop from APOBEC3G. Thus, a structural model is presented in which the mechanism of inhibition is both specific and competitive, by binding a pocket adjacent to the APOBEC3G active site, reacting with C321, and blocking access to substrate DNA cytosines. First-In-Class Small Molecule Inhibitors of the Single-Strand DNA Cytosine Deaminase APOBEC3G.,Li M, Shandilya SM, Carpenter MA, Rathore A, Brown WL, Perkins AL, Harki DA, Solberg J, Hook DJ, Pandey KK, Parniak MA, Johnson JR, Krogan NJ, Somasundaran M, Ali A, Schiffer CA, Harris RS ACS Chem Biol. 2012 Jan 17. PMID:22181350 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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