Reaction: [DNA]-3'-diphospho-5'-guanosine + H2O = [DNA]-3'-phosphate + GMP
Other name(s): aprataxin; DNA-3'pp5'G guanylate hydrolase; APTX (gene name); HNT3 (gene name)
Systematic name: [DNA]-3'-diphospho-5'-guanosine hydrolase (guanosine 5'-phosphate-forming)
Comments: Aprataxin is a DNA-binding protein that catalyses (among other activities) the 3' decapping of DNA-ppG (formed by EC 220.127.116.11, 3'-phosphate/5'-hydroxy nucleic acid ligase) . 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 its eventual release. The enzyme also possesses the activity of EC 18.104.22.168, adenosine-5'-diphospho-5'-[DNA] diphosphatase, and EC 22.214.171.124, guanosine-5'-diphospho-5'-[DNA] diphosphatase.
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
1. Das, U., Chauleau, M., Ordonez, H. and Shuman, S. Impact of DNA3'pp5'G capping on repair reactions at DNA 3' ends. Proc. Natl. Acad. Sci. USA 111 (2014) 11317-11322. [PMID: 25049385]
2. Chauleau, M., Jacewicz, A. and Shuman, S. DNA3'pp5'G de-capping activity of aprataxin: effect of cap nucleoside analogs and structural basis for guanosine recognition. Nucleic Acids Res. 43 (2015) 6075-6083. [PMID: 26007660]