Aprataxin is a DNA-binding protein that catalyses (among other activities) the 5' decapping of Gpp-DNA (formed by homologs of RtcB3 from the bacterium Myxococcus xanthus). The enzyme binds the guanylate group to a histidine residue at its active site, forming a covalent enzyme-nucleotide phosphate intermediate, followed by the hydrolysis of the guanylate from the nucleic acid and eventual release. The enzyme forms a 5'-phospho terminus that can be efficiently joined by "classical" ligases. The enzyme also possesses the activitiy of EC 3.6.1.71, adenosine-5'-diphospho-5'-[DNA] diphosphatase and EC 3.6.1.72, DNA-3'-diphospho-5'-guanosine diphosphatase.
History
EC 3.6.1.70 created 2017 as EC 3.1.11.8, transferred 2019 to EC 3.6.1.70
Characterization of 3'-Phosphate RNA Ligase Paralogs RtcB1, RtcB2, and RtcB3 from Myxococcus xanthus Highlights DNA and RNA 5'-Phosphate Capping Activity of RtcB3.