Identification of residues potentially involved in optical shifts in the water-soluble chlorophyll-a binding protein through molecular dynamics simulations
Bibliographic record
Abstract
Abstract Reversible light- and thermally-induced spectral shifts are universally observed in a wide variety of pigment-protein complexes, at temperatures ranging from cryogenic to ambient. They can be observed either directly, in single-molecule spectroscopy experiments, or via non-photochemical spectral hole burning. These shifts are important to understand, for example, to gain a clearer picture of the primary processes of photosynthesis, or of general features of the protein energy landscapes. In this article, we have employed large-scale molecular dynamics simulations of a prototypical pigment-protein complex to better understand these shifts at a molecular scale. Although multiple mechanisms have been proposed over the years, no verification of these proposals via MD simulations has thus far been performed; our work represents the first step in this direction. The common requirement for all these mechanisms is the presence of doublewell (or multiple-well) features of the protein energy landscapes. In this work, from large-scale molecular dynamics simulations of the Water-Soluble Chlorophyll-binding Protein complex, we identified side chain rotations of certain amino acid residues as likely candidates for relevant multi-well landscape features. The protein free energy landscapes associated with side chain rotations feature energy barriers of around 1100- 1600 cm − 1 , in agreement with optical spectroscopy results, with the most promising residue type associated with experimental signatures being serine, which possesses a symmetric landscape and moment of inertia of a relevant magnitude.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".