Bibliographic record
Abstract
The integrity and stability of DNA is essential to life since it stores genetic information in every living cell. Chemicals from the environment will assault DNA to form various types of DNA damage, ranging from small covalent crosslinks between neighboring DNA bases as seen in cyclobutane pyrimidine dimers, to big bulky adducts derived from benzo[a]pyrene. This resultant damage will lead to replication block and mutation if remain unrepaired and will eventually cause cancer or other genetic diseases. The work presented in this dissertation has illustrated the important role of the AlkB family DNA repair enzymes in cancer and Wilson’s Disease. In addition, we discovered these enzymes can modify epigenetic markers that affect DNA regulation. We also studied sequence-dependent conformational heterogeneity of aminobiphenyl adduct on DNA replication. The AlkB family DNA repair enzyme is a family of α-ketoglutarate (αKG)- and non-heme iron-dependent dioxygenases. Among all the homologs in this family, human ALKBH2 and ALKBH3, and E. coli AlkB have been proved to be the major enzymes that directly remove the alkyl adducts from alkylated DNA bases like 3-methylcytosine (3mC) and 1-methyladenine (1mA). These DNA adducts will cause strong replication block and mutagenicity in cell if AlkB enzymes are suppressed by toxicants. Cancer-associated mutations often lead to perturbed cellular energy metabolism and accumulation of potentially harmful oncometabolites. Chiral molecule 2-hydroxyglutarate (2HG) and its two stereoisomers (D- and L-2HG) have been demonstrated to competitively inhibit several αKG- and iron-dependent dioxygenases, including ALKBH2 and ALKBH3. In this work, we carried out detailed kinetic analyses of DNA repair reactions catalyzed by ALKBH2, ALKBH3 and the bacterial AlkB in the presence of D- and L-2HG in both double and single stranded DNA contexts. We not only determined kinetic parameters of inhibition, including kcat, KM, and Ki, but also correlated the relative concentrations of 2HG and αKG previously measured in tumor cells with the inhibitory effect of 2HG on the AlkB family enzymes. Both D- and L-2HG significantly inhibited the human DNA repair enzymes ALKBH2 and ALKBH3 under pathologically relevant concentrations (73-88% for D-2HG and 31-58% for L-2HG inhibition). This work provides a new perspective that the elevation of either D- or L-2HG in cancer cells may contribute to an increased mutation rate by inhibiting the DNA repair carried out by the AlkB family enzymes and thus exacerbate the genesis and progression of tumors. Another type of inhibitor of AlkB is toxic metals, such as, copper. Disturbed
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.005 | 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".