Theoretical Study of the Amazing Firefly Bioluminescence: The Formation and Structures of the Light Emitters
Bibliographic record
Abstract
Reaction mechanisms for the formation of the keto-form of oxyluciferin (OxyLH(2)) from the luciferin of fireflies via a dioxetanone intermediate are predicted using the B3LYP/6-31G theoretical method. The ring opening of a model dioxetanone and the decarboxylation proceed in one step via a singlet diradical transition structure with an activation barrier of 18.1 and an exothermicity of 90.8 kcal/mol. The S(0) --> S(1) vertical excitation energies predicted with time dependent density functional theory, TDDFT B3LYP/6-31+G, for the anionic and neutral forms of OxyLH(2) are in the range of 60 to 80 kcal/mol. These energetic results support the generally accepted theory of chemically initiated electron exchange luminescence (CIEEL). The chemical origin of the multicolor bioluminescence from OxyLH(2) is examined theoretically using the TDDFT B3LYP/6-31+G, ZINDO//B3LYP/6-31+G, and CIS/6-31G methods. A change in color of the light emission upon rotation of the two rings in the S(1) excited state of OxyLH(2) is unlikely because both possible emitters, the planar keto- and enol-forms, are minima on the S(1) potential energy surface. The participation of the enol-forms of OxyLH(2) in bioluminescence is plausible but not required to explain the multicolor emission. According to predictions at the TDDFT B3LYP level, the color of the bioluminescence depends on the polarization of the OxyLH(2) in the microenvironment of the enzyme-OxyLH(2) complex.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".