Mechanism of S-Nitrosation of Recombinant Human Brain Calbindin D<sub>28K</sub>
Bibliographic record
Abstract
Mass spectrometry and UV-vis absorption results support a mechanism for NO donation by S-nitrosoglutathione (GSNO) to recombinant human brain calbindin D(28K) (rHCaBP) that requires the presence of trace copper, added as either Cu,Zn-superoxide dismutase (CuZnSOD) or CuSO(4). The extent of copper-catalyzed rHCaBP S-nitrosation depends on the ratio of protein to GSNO and on the reaction time, and NO-transfer is prevented when copper chelators are present. CuZnSOD is an efficient catalyst of rHCaBP S-nitrosation, and the mechanism of CuZnSOD-catalyzed S-nitrosation involves reduction of the active-site Cu(II) by a number of the five free thiols in rHCaBP, giving rise to thiyl radicals. The Cu(I)ZnSOD formed catalyzes the reductive cleavage of GSNO present in solution to give GSH and release NO. rHCaBP thiyl radicals react with NO to yield the S-nitrosoprotein. Cu(II)ZnSOD is also reduced by GSH in a concentration-dependent manner up to 5 mM but not at higher GSH concentrations. However, unlike the rHCaBP thiyl radicals, GS(*) radicals dimerize to GSSG faster than their reaction with NO. The data presented here provide a biologically relevant mechanism for protein S-nitrosation by small S-nitrosothiols. S-nitrosation is rapidly gaining recognition as a major form of protein posttranslational modification, and the efficient S-nitrosation of CaBP by CuZnSOD/GSNO is speculated to be of neurochemical importance given that CaBP and CuZnSOD are abundant in neurons.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".