Determination of <i>Francisella tularensis</i> AcpB Acid Phosphatase Substrate Preferences
Bibliographic record
Abstract
The Francisella species encode 4 main acid phosphatases (Acp) that are potentially involved in pathogenesis through currently unknown mechanisms. Only 2 of these enzymes, AcpA and AcpC, have been biochemically characterized to date. In this work we describe the catalytic properties of Francisella tularensis AcpB utilizing an array of 120 phosphorylated substrates. In contrast to most acid phosphatases, the purified enzyme showed a narrow range of substrate preferences, with the highest affinity towards thiamine phosphate (Km = 150 μM). Francisella species do not possess a thiamine biosynthetic pathway even though vitamin B1 is indispensable in numerous cellular functions. Consequently, thiamine should be incorporated from the environment, in this case, from the host cell. Our results suggested that AcpB could provide the hydrolytic activity necessary to transform the nontransportable phosphorylated vitamin B1 present in tissues to a form that can be absorbed by the intracellular pathogen.
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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 | 0.001 |
| 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".