Nucleotidyltransferase (NT) domain of an uncharacterized subgroup of the Pol beta-like NT superfamily.
The Pol beta-like NT superfamily includes DNA polymerase beta and other family X DNA Polymerases, as well as Class I and Class II CCA-adding enzymes, RelA- and SpoT-like ppGpp synthetases and hydrolases, 2'5'-oligoadenylate (2-5A)synthetases, Escherichia coli adenylyltransferase (GlnE), Escherichia coli uridylyl transferase (GlnD), poly(A) polymerases, terminal uridylyl transferases, Staphylococcus aureus kanamycin nucleotidyltransferase, and similar proteins. Proteins belonging to this subgroup are uncharacterized. In the majority of the Pol beta-like superfamily NTs, two carboxylates, Dx[D/E], together with a third more distal carboxylate, coordinate two divalent metal cations essential for catalysis. These divalent metal ions are involved in a two-metal ion mechanism of nucleotide addition. These carboxylate residues are conserved in this subgroup.