Tuning Maps for Two-Photon Absorption Cross Sections of Canonical and Non-Canonical Fluorescent Protein Chromophores
Bibliographic record
Abstract
Two-photon absorption (2PA) spectroscopy, which involves the simultaneous absorption of a pair of photons, is an important area of research in biological chromophores. This work offers a perspective on how electrostatic interactions influence the 2PA response of fluorescent protein (FP) chromophores, demonstrating the role of their surrounding environment in modulating 2PA optical properties. In this work, we present electrostatic tuning maps, created by placing partial charges along the Van der Waals radii of eight different chromophores: Green FP (neutral and anion), Red FP (neutral and anion), mBlueberry FP, Kusabira orange FP, and two non-canonical chromophores, a hydroxyquinolone derivative, and the chromophore of Gold FP. 2PA cross sections (σ2PA) were calculated at the CAM-B3LYP(D3BJ)/aug-cc-pVDZ level of theory. The results show that the influence of point charges varies with their location, leading to substantial increases or decreases in the obtained σ2PA. Upon initial investigation, neutral chromophores tend to increase their σ2PA when positive point charges are present close to the imidazolinone group, while lowering their σ2PA when they are present near the benzylidene ring. In contrast, anionic species show an opposite trend. Using a positive or negative point charge has the opposite effect as well, increasing or decreasing σ2PA by relatively the same amount. These maps aid in understanding how electrostatic interactions influence 2PA responses, providing a framework for guiding structural modifications to the protein environment as well as the design and optimization of 2PA probes.
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".