Protein bL38 facilitates incorporation of uL6 during assembly of the 50S subunit in <i>Flavobacterium johnsoniae</i>
Bibliographic record
Abstract
Previous studies of the 70S ribosome from Flavobacterium johnsoniae revealed a novel ribosomal protein, bL38, which interacts with uL6 on the 50S subunit. This 5.6 kDa protein is conserved across the Bacteroidia and encoded downstream of bL28 and bL33 in a three-gene operon. Here, we show that bL38 is critical for the growth of F. johnsoniae, and depletion of bL38 leads to accumulation of immature 50S particles, which lack uL6 and retain precursor rRNA sequences. Cryo-EM analysis of these particles reveals several putative assembly intermediates, all showing an absence of electron density for uL6 and the entire uL12 stalk region and additional densities corresponding to the unprocessed ends of the pre-23S rRNA. Extra copies of the uL6 gene can rescue the phenotypes caused by bL38 depletion, suggesting that bL38 facilitates uL6 incorporation during 50S subunit biogenesis. Cryo-EM analysis of 50S particles from this rescued strain reveals nearly twice as many intermediates, suggesting a broader and more robust assembly landscape. Differential scanning fluorimetry shows that uL6 of F. johnsoniae is intrinsically unstable, and bL38 increases the melting temperature of uL6 by 12°C. Collectively, these data suggest that bL38 binds and stabilizes uL6, thereby promoting 50S biogenesis in the Bacteroidia.
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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".