The trans-membrane 17βHSD7: Kinetic study and preliminary crystallization data
Bibliographic record
Abstract
Human 17β-Hydroxysteroid dehydrogenase type 7 (h17HSD7) is a transmembrane enzyme belonging to the large, phylogenetically related protein family of short-chain dehydrogenases/reductases (SDR). In this study, h17HSD7 was expressed, purified, and the steady-state kinetics was studied. Here we report a purification method of the transmembrane enzyme using FPLC equipment with a combination of detergents to obtain homogeneous protein. We also report steady-state kinetics for h17HSD7 at 37 degrees Celsius and pH 7.5, using a homogeneous enzyme preparation with estrone (E1), or dihydrotestosterone (DHT) as substrate and NADPH as the cofactor. Kinetic studies made over a wide range of concentrations of both steroids (2microM to 60microM) revealed that E1 (Km= 12microM) has a higher apparent affinity for the h17BHSD7 compared to DHT (Km= 44microM). Crystallization of h17HSD7 in complex with high concentration of steroids to saturate the enzyme in the drop as low apparent affinity of both steroids was found in kinetic study. Some preliminary crystals were obtained by hanging-drop and diffracted at synchrotron facility (Maximum resolution: 2.95Å , Space group: H 3 2, Average unit cell: 120.74 120.74 201.94 90 90 90, Mosaicity : 0.51).
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".