PprA: A Key Protein in Extreme Radioresistance of Deinococcus
Bibliographic record
Abstract
DNA double‐strand breaks (DSBs) represent the most severe form of chromosomal damage. In higher organisms, one DSB represents a lethal event. This severity is broadly conserved with sensitivities ranging from one to only a few DSBs. Bacteria of the genus Deinococcus represent an unusual exception and are able to withstand extremely high levels of DSBs caused by ionizing radiation, UV radiation, and genotoxic chemicals. The extraordinary radioresistance of Deinococcus results from the capacity of the organism to efficiently repair DSBs. The repair mechanism responsible for this remarkable damage tolerance is currently poorly understood. Several genes have been identified as being both unique and essential for repair within Deinococcus species. Of these, a defect in ppra has been demonstrated to be particularly important for damage recovery. The goal of this work was to better understand the repair mechanism through which Deinococcus is able to recover from DNA damage through biochemical characterization of PprA. Here we characterize the interaction of PprA with DNA. EMSA experiments were done to determine the length‐dependence, as well as DNA end preference of PprA binding with DNA. PprA was also shown to form bundles of long fibrous filaments by transmission electron microscopy. Implications for how these filaments function in DNA repair are discussed. Characterizing the filament formation and DNA binding activity of PprA is essential to clarify its proposed function in bridging and aligning DNA in Deinococcus genome repair.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".