Details
- Autor(en) / Beteiligte
- Titel
- Molecular basis for DarT ADP-ribosylation of a DNA base
- Ist Teil von
- Nature (London), 2021-08, Vol.596 (7873), p.597
- Ort / Verlag
- England
- Erscheinungsjahr
- 2021
- Link zum Volltext
- Quelle
- MEDLINE
- Beschreibungen/Notizen
- ADP-ribosyltransferases use NAD to catalyse substrate ADP-ribosylation , and thereby regulate cellular pathways or contribute to toxin-mediated pathogenicity of bacteria . Reversible ADP-ribosylation has traditionally been considered a protein-specific modification , but recent in vitro studies have suggested nucleic acids as targets . Here we present evidence that specific, reversible ADP-ribosylation of DNA on thymidine bases occurs in cellulo through the DarT-DarG toxin-antitoxin system, which is found in a variety of bacteria (including global pathogens such as Mycobacterium tuberculosis, enteropathogenic Escherichia coli and Pseudomonas aeruginosa) . We report the structure of DarT, which identifies this protein as a diverged member of the PARP family. We provide a set of high-resolution structures of this enzyme in ligand-free and pre- and post-reaction states, which reveals a specialized mechanism of catalysis that includes a key active-site arginine that extends the canonical ADP-ribosyltransferase toolkit. Comparison with PARP-HPF1, a well-established DNA repair protein ADP-ribosylation complex, offers insights into how the DarT class of ADP-ribosyltransferases evolved into specific DNA-modifying enzymes. Together, our structural and mechanistic data provide details of this PARP family member and contribute to a fundamental understanding of the ADP-ribosylation of nucleic acids. We also show that thymine-linked ADP-ribose DNA adducts reversed by DarG antitoxin (functioning as a noncanonical DNA repair factor) are used not only for targeted DNA damage to induce toxicity, but also as a signalling strategy for cellular processes. Using M. tuberculosis as an exemplar, we show that DarT-DarG regulates growth by ADP-ribosylation of DNA at the origin of chromosome replication.
- Sprache
- Englisch
- Identifikatoren
- eISSN: 1476-4687DOI: 10.1038/s41586-021-03825-4Titel-ID: cdi_pubmed_primary_34408320
- Format
- –
- Schlagworte
- Adenosine Diphosphate Ribose - metabolism, ADP-Ribosylation, Antitoxins, Bacterial Proteins - chemistry, Bacterial Proteins - metabolism, Bacterial Toxins, Base Sequence, Biocatalysis, DNA - chemistry, DNA - genetics, DNA - metabolism, DNA Adducts - chemistry, DNA Adducts - metabolism, DNA Damage, DNA Repair, DNA Transposable Elements - genetics, DNA, Bacterial - chemistry, DNA, Bacterial - genetics, DNA, Bacterial - metabolism, Models, Molecular, Mycobacterium - enzymology, Mycobacterium - genetics, Nitrogen - chemistry, Nitrogen - metabolism, Poly(ADP-ribose) Polymerases - chemistry, Replication Origin - genetics, Substrate Specificity, Thermus - enzymology, Thymidine - chemistry, Thymidine - metabolism, Thymine - chemistry, Thymine - metabolism