Euglena Light-Harvesting Complexes Are Encoded by Multifarious Polyprotein mRNAs that Evolve in Concert
Bibliographic record
Abstract
Light-harvesting complexes (LHCs) are a superfamily of chlorophyll- and carotenoid-binding proteins that are responsible for the capture of light energy and its transfer to the photosynthetic reaction centers. Unlike those of most eukaryotes, the LHCs of Euglena gracilis are translated from large mRNAs, producing polyprotein precursors consisting of multiple concatenated LHC subunits that are separated by conserved decapeptide linkers. These precursors are posttranslationally targeted to the chloroplast and cleaved into individual proteins. We analyzed expressed sequence tags from Euglena to further characterize the structural features of the LHC polyprotein-coding genes and to examine the evolution of this multigene family. Of the 19 different LHC transcriptional units we detected, 17 encoded polyproteins composed of both tandem and nontandem repeats of LHC subunits; organizations that likely occurred through unequal crossing-over. Of the 2 nonpolyprotein-encoding LHC transcripts detected, 1 evolved from the truncation of a polyprotein-coding gene. Duplication of LHC polyprotein-coding genes was particularly important in the LHCI gene family where multiple paralogous sequences were detected. Intriguingly, several of the individual LHC-coding subunits both within and between transcriptional units appeared to be evolving in concert, suggesting that gene conversion has been a significant mechanism for LHC evolution in Euglena.
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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 | 0.000 | 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) | 0.000 | 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".