The AlkB Family of Fe(II)/α-Ketoglutarate-dependent Dioxygenases: Repairing Nucleic Acid Alkylation Damage and Beyond

The AlkB family of Fe(II)- and alpha-ketoglutarate-dependent dioxygenases is a class of ubiquitous direct reversal DNA repair enzymes that remove alkyl adducts from nucleobases by oxidative dealkylation. The prototypical and homonymous family member is an Escherichia coli "adaptive response" protein that protects the bacterial genome against alkylation damage. AlkB has a wide variety of substrates, including monoalkyl and exocyclic bridged adducts. Nine mammalian AlkB homologs exist (ALKBH1-8, FTO), but only a subset functions as DNA/RNA repair enzymes. This minireview presents an overview of the AlkB proteins including recent data on homologs, structural features, substrate specificities, and experimental strategies for studying DNA repair by AlkB family proteins.