A general protein <scp><i>O</i></scp>‐glycosylation system within the <scp><i>B</i></scp><i>urkholderia cepacia</i> complex is involved in motility and virulence
Bibliographic record
Abstract
Bacteria of the Burkholderia cepacia complex (Bcc) are pathogens of humans, plants, and animals. Burkholderia cenocepacia is one of the most common Bcc species infecting cystic fibrosis (CF) patients and its carriage is associated with poor prognosis. In this study, we characterized a general O-linked protein glycosylation system in B. cenocepacia K56-2. The PglLBc O-oligosaccharyltransferase (O-OTase), encoded by the cloned gene bcal0960, was shown to be capable of transferring a heptasaccharide from the Campylobacter jejuni N-glycosylation system to a Neisseria meningitides-derived acceptor protein in an Escherichia coli background, indicating that the enzyme has relaxed specificities for both the sugar donor and protein acceptor. In B cenocepacia K56-2, PglLBc is responsible for the glycosylation of 23 proteins involved in diverse cellular processes. Mass spectrometry analysis revealed that these proteins are modified with a trisaccharide HexNAc-HexNAc-Hex, which is unrelated to the O-antigen biosynthetic process. The glycosylation sites that were identified existed within regions of low complexity, rich in serine, alanine, and proline. Disruption of bcal0960 abolished glycosylation and resulted in reduced swimming motility and attenuated virulence towards both plant and insect model organisms. This study demonstrates the first example of post-translational modification in Bcc with implications for pathogenesis.
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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) | 0.000 | 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 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".