Complex Conformational Interplay for Parkin Activation is Revealed by 19F NMR Spectroscopy
Bibliographic record
Abstract
Parkin is a 52 kDa RING-Between-RING E3 ligase that ubiquitinates proteins at the outer mitochondrial membrane in response to oxidative stress. Part of a neuroprotective pathway, over 100 mutations in the PRKN gene have been associated with Early Onset Parkinson’s Disease. To be fully active parkin requires interaction with phosphorylated ubiquitin and phosphorylation of its N-terminal Ubl domain, both dependent on the PINK1 kinase. Along with recruitment of an E2∼Ubiquitin conjugate these events form a ∼90 kDa complex, undergoing a series of conformational changes that regulate transthiolation of ubiquitin from the E2 enzyme to the catalytic domain in parkin (Rcat) prior to substrate labeling. Numerous crystal and NMR structures have captured snapshots of parkin activation and its catalytic mechanism, yet questions surrounding the relative abundance, timing and interplay of parkin conformations remain. Further, most studies use truncated versions of the E3 ligase that may hide details of conformational dependencies. To examine parkin through its activation cycle from inactive (autoinhibited) to E2∼Ubiquitin binding states we incorporated 5- 19 F-tryptophan into the full-length enzyme and used 19 F NMR spectroscopy to identify structural and dynamics changes. Using chemical shift perturbation and T2 analysis, we show that phosphorylation of parkin leads to a population of unbound and bound forms of the phosphorylated Ubl domain and that release of the catalytic Rcat domain is dependent upon E2∼Ub conjugate binding. This study shows the unique abilities of 19 F NMR spectroscopy to provide details of the structural rearrangements required for catalysis for the large E3 ligase parkin.
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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) | 0.002 | 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".