An alpha+beta fold domain found C-terminal to the MazG superfamily pyrophosphatase domain. The domain has a conserved DxYRxHDxxH motif indicative of catalytic activity. Based on its broader context in DNA modification, it is proposed to function as a nucleotide kinase [1].

1: Computational identification of novel biochemical systems involved in oxidation, glycosylation and other complex modifications of bases in DNA. Iyer LM, Zhang D, Burroughs AM, Aravind L; Nucleic Acids Res. 2013;41:7635-7655. PMID:23814188