The X‐ray structure of photosystem II reveals a novel electron transport pathway between P680, cytochrome <i>b</i><sub>559</sub> and the energy‐quenching cation, Chl<sub>Z</sub><sup>+</sup>
Bibliographic record
Abstract
When water oxidation by photosystem II (PSII) is impaired, an oxidized chlorophyll (Chl(Z)(+)) is formed that quenches excitation and may prevent photodamage. Both the identification of this Chl(+) and the mechanism of its oxidation and reduction are controversial. Using the available X-ray structures of PSII we calculated the efficiency of two proposed quenchers, Chl(Z)(+)(D1) and Chl(Z)(+)(D2). Of these two, only Chl(Z)(+)(D1) can quench to the degree observed experimentally. We also identify a chain of closely spaced pigments in the structure from Thermosynechococcus vulcanus that we propose to form a novel electron transport pathway between Chl(Z)(D1), beta-carotene, P680(+) and cytochrome b(559).
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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 | 0.001 | 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 | 0.001 | 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) | 0.000 | 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".