| Comment | This model represents a family of proteins and protein domains which catalyze the dephosphorylation of DNA 3'-phosphates. It is believed that this activity is important for the repair of single-strand breaks in DNA caused by radiation or oxidative damage. This domain is often (TIGR01663 [1,2]), but not always [3,4] linked to a DNA 5'-kinase domain.
The central phosphatase domain is a member of the IIIA subfamily (TIGR01662) of the haloacid dehalogenase (HAD) superfamily of aspartate-nucleophile hydrolases. As is common in this superfamily, the enzyme is magnesium dependent. A difference between this enzyme and other HAD-superfamily phosphatases is in the third conserved catalytic motif which usually contains two conserved aspartate residues believed to be involved in binding the magnesium ion. Here, the second aspartate is usually replaced by an arginine residue which may indicate an interaction with the phosphate backbone of the substrate. Alternatively, there is an additional conserved aspartate downstream of the ususal site which may indicate slightly different fold in this region. |
| References | RN [1]
RM PMID: 10446192
RT Molecular cloning of the human gene, PNKP, encoding a polynucleotide kinase 3'-phosphatase and evidence for its role in repair of DNA strand breaks caused by oxidative damage.
RA Jilani A, Ramotar D, Slack C, Ong C, Yang XM, Scherer SW, Lasko DD.
RL J Biol Chem 1999 Aug 20;274(34):24176-86
RN [2]
RM PMID: 10446193
RT Molecular characterization of a human DNA kinase.
RA Karimi-Busheri F, Daly G, Robins P, Canas B, Pappin DJ, Sgouros J, Miller GG, Fakhrai H, Davis EM, Le Beau MM, Weinfeld M.
RL J Biol Chem 1999 Aug 20;274(34):24187-94
RN [3]
RM PMID: 11278831
RT Uncoupling of 3'-phosphatase and 5'-kinase functions in budding yeast. Characterization of Saccharomyces cerevisiae DNA 3'-phosphatase (TPP1).
RA Vance JR, Wilson TE.
RL J Biol Chem 2001 May 4;276(18):15073-81
RN [4]
RM PMID: 11278717
RT A plant 3'-phosphoesterase involved in the repair of DNA strand breaks generated by oxidative damage.
RA Betti M, Petrucco S, Bolchi A, Dieci G, Ottonello S.
RL J Biol Chem 2001 May 25;276(21):18038-45 |
