A DNA Sequence Recognition Loop on APOBEC3A Controls Substrate Specificity

A DNA Sequence Recognition Loop on APOBEC3A Controls Substrate Specificity

APOBEC3A (A3A), one of the seven-member APOBEC3 family of cytidine deaminases, lacks strong antiviral activity against lentiviruses but is a potent inhibitor of adeno-associated virus and endogenous retroelements. In this report, we characterize the biochemical properties of mammalian cell-produced and catalytically active E. coli-produced A3A. The enzyme binds to single-stranded DNA with a Kd ...

Substrate sequence selectivity of APOBEC3A implicates intra-DNA interactions

NMR structure of human restriction factor APOBEC3A reveals substrate binding and enzyme specificity

Human APOBEC3A is a single-stranded DNA cytidine deaminase that restricts viral pathogens and endogenous retrotransposons, and has a role in the innate immune response. Furthermore, its potential to act as a genomic DNA mutator has implications for a role in carcinogenesis. A deeper understanding of APOBEC3A's deaminase and nucleic acid-binding properties, which is central to its biological act...

A MODEL FOR THE BASIC HELIX- LOOPHELIX MOTIF AND ITS SEQUENCE SPECIFIC RECOGNITION OF DNA

A three dimensional model of the basic Helix-Loop-Helix motif and its sequence specific recognition of DNA is described. The basic-helix I is modeled as a continuous ?-helix because no ?-helix breaking residue is found between the basic region and the first helix. When the basic region of the two peptide monomers are aligned in the successive major groove of the cognate DNA, the hydrophobi...

Human placental DNA methyltransferase: DNA substrate and DNA binding specificity.

We have partially purified a DNA methyltransferase from human placenta using a novel substrate for a highly sensitive assay of methylation of hemimethylated DNA. This substrate was prepared by extensive nick translation of bacteriophage XP12 DNA, which normally has virtually all of its cytosine residues replaced by 5-methylcytosine (m5C). Micrococcus luteus DNA was just as good a substrate if i...