Functional chimera of porcine pepsin prosegment and Plasmodium falciparum plasmepsin II
Bibliographic record
Abstract
Proplasmepsin II (zPMII) represents a unique member of the aspartic proteinase family, with a prosegment-enzyme interaction that is thus far unique among the pepsin-like proteases. The role of the prosegment in aspartic proteinase structure and function was investigated by generating two chimeric proteins, one with the pepsinogen prosegment fused to the mature region of PMII (pepproPMII) and a second with the prosegment of PMII fused to pepsin (PMIIpropep). Both chimeras were expressed using Escherichia coli; however, PMIIpropep was extremely unstable suggesting protein misfolding. Alternatively, pepproPMII was capable of both autoactivation and hydrolysis of a synthetic substrate. Similarly, when the PMII enzyme was expressed without a prosegment, it too exhibited activity against the synthetic enzyme. CD measurements indicated that pepproPMII had reduced thermal stability when compared with zPMII. This reduction of temperature stability may have resulted from the inability of the pepsinogen prosegment to stabilize the C-terminal domain of the PMII enzyme. The ability of PMII to fold in the presence of a completely non-homologous prosegment and in its absence suggests that prosegment is not critical to obtaining a functional enzyme in all pepsin-like enzymes but likely plays a role in protein stabilization.
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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 | 0.001 |
| 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".