A Red‐Light Azobenzene Di‐Maleimide Photoswitch: Pros and Cons
Bibliographic record
Abstract
Azobenzene‐containing intramolecular cross‐linkers with maleimide functional groups (e.g., azobenzene di‐maleimide (ABDM)) have been used successfully for photocontrol of protein conformation and activity. However, the ABDM cross‐linker requires short wavelength UV light (340 nm) for photoisomerization, which is highly scattered and can be absorbed by biological materials. In addition, the maleimide functional groups of ABDM are expected to lead to a mixture of stereoisomeric products upon cross‐linking and these may undergo ring‐opening via hydrolysis. This study reports the design and synthesis of a tetra‐ortho‐methoxy substituted ABDM cross‐linker, which can be photoisomerized using red light (617 nm) and blue light (450 nm), thereby avoiding the use of UV. This new cross‐linker is used to cross‐link a peptide, 30ER that undergoes helix–coil transitions. As predicted, hydrolyzed succinimide cross‐linked products are observed by mass spectrometry. However, although, hydrolyzed products are present, and a mixture of stereoisomers presumably forms, photoisomerization of the cross‐linker nevertheless enables control of peptide helical conformation using red light. Thus, azobenzene di‐maleimides are practically useful, although chemically ill‐defined, photoswitchable cross‐linkers.
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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 | 0.000 |
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".