Purification, crystallization and preliminary X-ray analysis of the<i>Escherichia coli</i>glucose-1-phosphatase
Bibliographic record
Abstract
Encoded by the agp gene, Escherichia coli glucose-1-phosphatase hydrolyzes glucose-1-phosphate in the periplasmic space of the bacterium. It is a potential drug-design target because inositol phosphatases have been identified as important virulence determinants in several human and animal pathogens. The enzyme was isolated and purified to homogeneity from a strain of E. coli CU1867 (an appA-deficient mutant). Crystals were obtained overnight by the equilibrium vapour-diffusion method from a solution containing 10 mg ml(-1) enzyme, 1.2 M ammonium sulfate and 25% polyethylene glycol monomethyl ether 5000 in 0.1 M MES at pH 6.5. The crystals belong to space group R3, with unit-cell parameters a = b = 156.0, c = 92.2 A. The diffraction limit was 2.6 A at a rotating-anode X-ray source; a 2.7 A resolution data set has been collected using light mineral oil as a cryoprotectant. The data set was 95.2% complete, with an R(sym) of 0.058. There were two monomers of glucose-1-phosphatase in the asymmetric unit, which correspond to a V(M) of 2.36 A Da(-1) and 47.5% solvent content. Self-rotation analysis unambiguously shows a twofold non-crystallographic symmetry.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.007 |
| Science and technology studies | 0.001 | 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) | 0.001 | 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 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".