Structure of the type VI secretion protein VgrS from <i>Salmonella</i> Typhimurium
Bibliographic record
Abstract
SUMMARY Enteric bacterial pathogens employ various strategies to colonize the intestine and cause diseases ranging from gastroenteritis to systemic infections. For example, Salmonella enterica utilizes a nanomachine known as the type VI secretion system (T6SS) to facilitate colonization of the host gut. However, the varied mechanistic details of how the T6SS is loaded with effector proteins remains to be elucidated. Here, we present an X-ray crystal structure of the Salmonella Typhimurium VgrG (VgrS) that serves as platform for T6SS effector loading. Compared to other known structures of VgrG proteins, the VgrS trimer adopts an alternative open conformation composed of a domain-swap between the monomers in the gp27 region. Additionally, a comparative structural analysis of VgrS with other VgrG proteins reveals molecular variations that may contribute to specific effector loading mechanisms. Our structural data and molecular analysis highlight the observation that the T6SS of each bacterial species or strain is unique.
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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 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".