CATH Classification

Domain Context

CATH Clusters

Superfamily HIT-like
Functional Family aprataxin isoform X2

Enzyme Information

3.1.12.2
DNA-3'-diphospho-5'-guanosine diphosphatase.
based on mapping to UniProt Q7Z2E3
(DNA)-3'-diphospho-5'-guanosine + H(2)O = (DNA)-3'-phosphate + GMP.
-!- Aprataxin is a DNA-binding protein that catalyzes (among other activities) the 3' decapping of DNA-ppG (formed by EC 6.5.1.8). -!- 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 3.1.11.7 and EC 3.1.11.8.
3.1.11.7
Adenosine-5'-diphospho-5'-(DNA) diphosphatase.
based on mapping to UniProt Q7Z2E3
(1) Adenosine-5'-diphospho-5'-(DNA) + H(2)O = AMP + phospho-5'-(DNA). (2) Adenosine-5'-diphospho-5'-(ribonucleotide)-(DNA) + H(2)O = AMP + 5'-phospho-(ribonucleotide)-(DNA).
-!- Aprataxin is a DNA-binding protein involved in different types of DNA break repair. -!- The enzyme acts (among other activities) on abortive DNA ligation intermediates that contain an adenylate covalently linked to the 5'-phosphate DNA terminus. -!- It also acts when the adenylate is covalently linked to the 5'-phosphate of a ribonucleotide linked to a DNA strand, which is the result of abortive ligase activty on products of EC 3.1.26.4, an enzyme that cleaves RNA-DNA hybrids on the 5' side of the ribonucleotide found in the 5'-RNA-DNA-3' junction. -!- Aprataxin binds the adenylate group to a histidine residue within the active site, followed by its hydrolysis from the nucleic acid and eventual release, leaving a 5'-phosphate terminus that can be efficiently rejoined. -!- The enzyme also possesses the activities of EC 3.1.11.8 and EC 3.1.12.2.

UniProtKB Entries (1)

Q7Z2E3
APTX_HUMAN
Homo sapiens
Aprataxin

PDB Structure

PDB 4NDG
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Aprataxin resolves adenylated RNA-DNA junctions to maintain genome integrity.
Tumbale, P., Williams, J.S., Schellenberg, M.J., Kunkel, T.A., Williams, R.S.
Nature