The Dramatic Modulatory Role of the 2'N Substitution of the Terminal Amino Hexose of Globotetraosylceramide in Determining Binding by Members of the Verotoxin Family
Bibliographic record
Abstract
Although globotetraosylceramide (Gb4) is only recognized by a single member of the verotoxin family namely, the pig edema disease toxin (VT2e), removal of the acetyl group from the terminal N-acetyl hexosamine of Gb4 to generate the free amino sugar containing species (aminoGb4) results in the generation of a glycolipid preferentially recognized by all members of the verotoxin family (i.e., VT1, VT2, VT2c, and VT2e). GT3, a site-specific mutant of VT2e, in which Gb4 recognition is lost but Gb3 binding is retained, also binds aminoGb4. We have now compared the binding of VT1, VT2, VT2e, and GT3 to a series of aminoGb4 derivatives using a TLC overlay technique. DimethylaminoGb4 is bound by VT1 and VT2 but not VT2e or GT3; formylaminoGb4 binds all toxins but poorly to VT2 and preferentially VT2e; trifluoroacetylaminoGb4 binds only VT2e and GT3; isopropylaminoGb4 binds VT1 and poorly to VT2; benzylaminoGb4 binds all four toxins. Thus, there is a marked distinction between the permissible amino substitutions for VT1 and VT2e binding. GT3 is a hybrid between these in that, according to the substitution, it behaves similarly either to VT1 or to VT2e. For each species, GT3 does not however, show a hybrid binding between that of VT1 and VT2e. Analysis of the binding as a function of pH shows opposite effects for VT1 and VT2e: decreased pH increases VT1, but decreases VT2e receptor glycolipid binding.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 teacher head, 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".