Cytochrome b5 from Giardia lamblia
Bibliographic record
Abstract
The protozoan intestinal parasite Giardia lamblia lacks mitochondria and the ability to make haem yet encodes several putative haem-binding proteins, including three of the cytochrome b(5) family. We cloned one of these (gCYTb5-I) and expressed it within Escherichia coli as a soluble holoprotein. UV-visible and resonance Raman spectra of gCYTb5-I resemble those of microsomal cytochrome b(5), and homology modelling supports a structure in which a pair of invariant histidine residues act as axial ligands to the haem iron. The reduction potential of gCYTb5-I is -165 mV vs. SHE and is relatively low compared to most values (-110 to +80 mV) for this class of protein. The amino- and carboxy-terminal sequences that flank the central haem-binding core of the Giardia cytochromes are highly charged and differ from those of other family members. A core gCYTb5-I variant lacking these flanking sequences was also able to bind haem. The presence of one actual and two probable functional cytochromes b(5) in Giardia is evidence of uncharacterized cytochrome-mediated metabolic processes within this medically important protist.
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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 | 0.000 |
| 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".