Activation and deactivation of vibronic channels in intact phycocyanin rods
Bibliographic record
Abstract
We investigated the excitation modes of the light-harvesting protein phycocyanin (PC) from Thermosynechococcus vulcanus in the crystalline state using UV and near-infrared Raman spectroscopy. The spectra revealed the absence of a hydrogen out-of-plane wagging (HOOP) mode in the PC trimer, which suggests that the HOOP mode is activated in the intact PC rod, while it is not active in the PC trimer. Furthermore, in the PC trimer an intense mode at 984 cm(-1) is assigned to the C-C stretching vibration while the mode at 454 cm(-1) is likely due to ethyl group torsion. In contrast, in the similar chromophore phytochromobilin the C5,10,15-D wag mode at 622 cm(-1) does not come from a downshift of the HOOP. Additionally, the absence of modes between 1200 and 1300 cm(-1) rules out functional monomerization. A correlation between phycocyanobilin (PCB) and phycoerythrobilin (PEB) suggests that the PCB cofactors of the PC trimer appear in a conformation similar to that of PEB. The conformation of the PC rod is consistent with that of the allophycocyanin (APC) trimer, and thus excitonic flow is facilitated between these two independent light-harvesting compounds. This excitonic flow from the PC rod to APC appears to be modulated by the vibration channels during HOOP wagging, C = C stretching, and the N-H rocking in-plan vibration.
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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".