Inhibiting APOBEC3 activity with single-stranded DNA containing 2'-deoxyzebularine analogs.

作者：Kvach Maksim Vyacheslavovich; Barzak Fareeda M; Harjes Stefan; Schares Henry A M; Jameson Geoffrey B; Ayoub Alex M; Moorthy Ramkumar; Aihara Hideki; Harris Reuben S; Filichev Vyacheslav; Harki Daniel A; Harjes Elena

来源：Biochemistry, 2018.

DOI：10.1021/acs.biochem.8b00858

APOBEC3 enzymes form part of the innate immune system by deaminating cytosine to uracil in single-stranded DNA (ssDNA) and thereby preventing the spread of pathogenic genetic information. However, APOBEC mutagenesis is also exploited by viruses and cancer cells to increase rates of evolution, escape adaptive immune responses, and resist drugs. This raises the possibility of APOBEC3 inhibition as a strategy to augment existing antiviral and anticancer therapies. Here we show that, upon incorporation into short single-stranded (ss)DNAs, the cytidine nucleoside analog 2'-deoxy-zebularine (dZ) becomes capable of inhibiting the catalytic activity of selected APOBEC variants derived from APOBEC3A, APOBEC3B, and APOBEC3G supporting a mechanism in which ssDNA delivers dZ to the active site. Multiple experimental approaches, including isothermal titration calorimetry, fluorescence polarization, protein thermal shift, and NMR spectroscopy assays demonstrate nanomolar dissociation constants and low micromolar inhibition constants. These dZ containing ssDNAs constitute the first substrate-like APOBEC3 inhibitors and, together, comprise a platform for developing nucleic acid-based inhibitors with cellular activity.