PROTEIN- <i>O</i> -MANNOSYLATION BY NON-SEC/TAT SECRETION TRANSLOCONS IN ACTINOBACTERIA
Bibliographic record
Abstract
Abstract Protein- O -mannosylation (POM) is a form of O -glycosylation that is ubiquitous throughout all domains of life and has been extensively characterized in eukaryotic systems. However, in prokaryotes this process has only been investigated in terms of pathogenicity (in Mycobacterium tuberculosis ) even though there are many non-pathogenic bacteria that are known to regularly carry out POM. To date, there is no consensus on what benefit POM imparts to the non-pathogenic bacteria that can perform it. Though the generation of a POM deficient mutant of Corynebacterium glutamicum – a widely utilized and known mannosylating actinobacteria – this work shows that even closely related actinobacterial GT-39s (the enzymes responsible for the initiation of POM) can potentially have different activities and substrate specificities for targets of POM. Moreover, presented here is evidence that POM does not only occur in a SEC-dependent manner; POM also occurs with TAT and non-SEC secreted substrates in a specific and likely tightly regulated manner. Together these results highlight the need for further biochemical characterization of POM in these and other bacterial species to help elucidate the true nature of its biological functions. Importance Both the mechanism and overall cellular function of protein- O -mannosylation, a ubiquitous subset of O -glycosylation, is poorly understood in bacterial systems. In Mycobacterium tuberculosis and other pathogenic actinobacteria, numerous secreted virulence factors were identified as mannoproteins, with protein- O -mannosylation deficient mutants displaying a less virulent phenotype due to these proteins lacking the modification. However, these findings do not offer any explanations as to why non-pathogenic strains of actinobacteria also perform this modification as in these organisms it is seemingly dispensable. Corynebacterium glutamicum is a widely utilized, industrially relevant actinobacteria that also performs protein- O -mannosylation. This manuscript describes the utilization of C. glutamicum as a Gram-positive recombinant host for the in vivo study of actinobacterial protein- O -mannosylation and demonstrates the distinct lack of first-hand biochemical data of the process in prokaryotes.
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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".