Cloning, expression, and characterization of 5-aminolevulinic acid synthase from Rhodopseudomonas palustris KUGB306
Why this work is in the frame
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Bibliographic record
Abstract
The hemA gene encoding 5-aminolevulinic acid synthase (ALAS) was cloned from the genomic DNA of photosynthetic bacterium Rhodopseudomonas palustris KUGB306. The deduced protein (ALAS) of this gene contained 409 amino acids. The hemA gene was subcloned into an expression vector pGEX-KG and the encoded protein was overexpressed as a fusion protein with glutathione-S-transferase (GST) in Escherichia coli BL21. The recombinant ALAS was purified and isolated free of the fusion partner (GST) by affinity purification on glutathione-Sepharose 4B resin and cleavage of the purified fusion protein by thrombin protease. The optimum pH and temperature of the recombinant ALAS was found to be at pH 7.5–8.0 and 35–40 °C, respectively. The Km value of the enzyme was 2.01 mM for glycine and 49.55 μM for succinyl-CoA. The enzyme activity was strongly inhibited by Pb2+, Fe2+, Co2+, Cu2+, and Zn2+ at 1 mM, but slightly affected by Mg2+ and K+. The recombinant ALAS required pyridoxal 5′-phosphate (PLP) as a cofactor for catalysis. Removal of this cofactor led to complete loss of the activity. Ultraviolet–visible spectroscopy with the ALAS suggested the presence of an aldimine linkage between the enzyme and PLP.
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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 | 0.000 | 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) | 0.000 | 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 it