DNA3'pp5'G de-capping activity of aprataxin: Effect of cap nucleoside analogs and structural basis for guanosine recognition Journal Article
| Authors: | Chauleau, M.; Jacewicz, A.; Shuman, S. |
| Article Title: | DNA3'pp5'G de-capping activity of aprataxin: Effect of cap nucleoside analogs and structural basis for guanosine recognition |
| Abstract: | DNA3'pp5'G caps synthesized by the 3'-PO4/5'-OH ligase RtcB have a strong impact on enzymatic reactions at DNA 3'-OH ends. Aprataxin, an enzyme that repairs A5'pp5'DNA ends formed during abortive ligation by classic 3'-OH/5'-PO4 ligases, is also a DNA 3' de-capping enzyme, converting DNAppG to DNA(3')p and GMP. By taking advantage of RtcB's ability to utilize certain GTP analogs to synthesize DNAppN caps, we show that aprataxin hydrolyzes inosine and 6-O-methylguanosine caps, but is not adept at removing a deoxyguanosine cap. We report a 1.5 angstrom crystal structure of aprataxin in a complex with GMP, which reveals that: (i) GMP binds at the same position and in the same anti nucleoside conformation as AMP; and (ii) aprataxin makes more extensive nucleobase contacts with guanine than with adenine, via a hydrogen bonding network to the guanine O6, N1, N2 base edge. Alanine mutations of catalytic residues His147 and His149 abolish DNAppG de-capping activity, suggesting that the 3' de-guanylylation and 5' de-adenylylation reactions follow the same pathway of nucleotidyl transfer through a covalent aprataxin-(His147)-NMP intermediate. Alanine mutation of Asp63, which coordinates the guanosine ribose hydroxyls, impairs DNAppG decapping. © The Author(s) 2015. |
| Journal Title: | Nucleic Acids Research |
| Volume: | 43 |
| Issue: | 12 |
| ISSN: | 0305-1048 |
| Publisher: | Oxford University Press |
| Date Published: | 2015-07-13 |
| Start Page: | 6075 |
| End Page: | 6083 |
| Language: | English |
| DOI: | 10.1093/nar/gkv501 |
| PROVIDER: | scopus |
| PMCID: | PMC4499129 |
| PUBMED: | 26007660 |
| DOI/URL: | |
| Notes: | Export Date: 2 October 2015 -- Source: Scopus |
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