Purification and partial characterization of a novel, non‐AT1, non‐AT2 binding site for angiotensins in the rat brain
Bibliographic record
Abstract
The structure of the novel, non‐AT1, non‐AT2 binding site for angiotensins (Ang) (Brain Res. 2007, 1143: 83) is still unknown. We used Sar1‐p‐benzoyl‐L‐Phe8‐Ang II to specifically photolabel this protein in rat brain membranes. Photolabeled membrane pellet extracts were resolved by 7.5% SDS‐PAGE. The radioactive peak in the "Total" binding samples was 75‐80 kDa with negligible amounts of radioactivity at this point in corresponding "Non‐specific" samples. Gel cuts from the radioactive band from the "Total" samples were combined and radioactivity was extracted. The molecular weight of the semipurified binding site was not altered by glycopeptidase‐F indicating that the protein is not N‐glycosylated. Neither GTPgammaS nor GppNHP (at 50 µM) alter Ang II binding affinity for the binding site suggesting that it is not a G protein‐coupled receptor. The semipurified, radio‐photolabeled binding site was applied for 2D gel electrophoresis. The isoelectric point of the binding site was ~ 7.0. Cyanogen bromide hydrolysis of the protein gave 2 bands: 25 & 12.5 kDa, suggesting that there are 3 or more Met residues in this protein. Mass‐spectroscopic analysis of these digests should provide a partial amino acid sequence, revealing whether this is a known protein with a novel functionality, or if it is a novel brain protein. Supported by the Peptide Radioiodination Service Center of the University of Mississippi.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| 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 | 0.001 |
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".