Synthesis of Building Blocks and Oligonucleotides with {G}O<sup>6</sup>‐Alkyl‐O<sup>6</sup>{G} Cross‐Links
Bibliographic record
Abstract
This unit describes two methods for preparing oligonucleotides containing an O(6)-2'-deoxyguanosine-alkyl-O(6)-2'-deoxyguanosine interstrand cross-link by a solid-phase synthesis approach. Depending on the desired orientation of the cross-link in the DNA duplex, either a bis- or a mono-phosphoramidite synthesis strategy can be employed. Both procedures require the preparation of a protected 2'-deoxyguanosine-containing dimer where the two nucleosides are attached at the O(6)-atoms by an alkyl linker. This linker is introduced as a protected diol using two successive Mitsunobu reactions to produce a cross-linked amidite that is incorporated into an oligonucleotide via solid-phase synthesis. The use of a protected diol lends versatility to this method, as cross-links of variable chain length may be prepared. The bis-phosphoramidite approach is a direct method to preparing the cross-linked duplex, whereas the mono-phosphoramidite strategy requires additional manipulation of the solid support to prepare cross-linked oligonucleotides. Once all synthetic steps are completed, these oligonucleotides can then be removed from the solid support and deprotected, and then purified via ion-exchange HPLC to produce sufficient quantities of substrates that can be used in DNA repair studies.
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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) | 0.001 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.003 |
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".