An Integrated Imaging Probe Design: The Synthesis of <sup>99m</sup>Tc/Re‐Containing Macrocyclic Peptide Scaffolds
Bibliographic record
Abstract
β-Sheets account for over 30 % of all secondary structural conformations found in proteins. The intramolecular hydrogen bonding that exists between the two peptide strands is imperative in maintaining this secondary structure. With the proper design, cyclic peptides may act as scaffolds emulating active β-sheet regions, enabling investigation of their importance in molecular recognition and protein aggregation. Starting from Fmoc-Lys(Fmoc)-OH, macrocyclic peptides were synthesized on a solid support, with peptide-chain elongation extending from both the alpha and epsilon amines of the lysine. The branching peptides were cyclized with a pyridyl tridentate chelation core followed by coordination using [(99m) Tc/Re(CO)3 (H2 O)3 ](+) . Variable temperature (1) H NMR spectroscopy studies were performed, demonstrating that intramolecular hydrogen bonding exists between the two sides of the uncoordinated macrocyclic peptide scaffolds. Additionally, computational modelling and circular dichroism spectroscopic analysis revealed that the peptide backbone exists in a similar conformation both before and after metal coordination. The ability to seamlessly incorporate a tridentate chelation core into the backbone of a macrocyclic peptide, without disrupting the secondary structure, can greatly assist in the design of metal-centric peptidomimetic imaging agents. This novel integrated imaging probe approach may facilitate the investigation into protein-protein interactions using macrocyclic β-sheet scaffolds.
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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 | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".