ADP-Ribosylation of Cross-Linked Actin Generates Barbed-End Polymerization-Deficient F-Actin Oligomers
Bibliographic record
Abstract
Actin filament subunit interfaces are required for the proper interaction between filamentous actin (F-actin) and actin binding proteins (ABPs). The production of small F-actin complexes mimicking such interfaces would be a significant advance toward understanding the atomic interactions between F-actin and its many binding partners. We produced actin lateral dimers and trimers derived from F-actin and rendered polymerization-deficient by ADP-ribosylation of Arg-177. The degree of modification resulted in a moderate reduction in thermal stability. Calculated hydrodynamic radii were comparable to theoretical values derived from recent models of F-actin. Filament capping capabilities were retained and yielded pointed-end dissociation constants similar those of wild-type actin, suggesting native or near-native interfaces on the oligomers. Changes in DNase I binding affinity under low and high ionic strength suggested a high degree of conformational flexibility in the dimer and trimer. Polymer nucleation activity was lost upon ADP-ribosylation and rescued upon enzyme-mediated deADP-ribosylation, or upon binding to gelsolin, suggesting that interactions with actin binding proteins can overcome the inhibiting activities of ADP-ribosylation. The combined strategy of chemical cross-linking and ADP-ribosylation provides a minimalistic and reversible approach to engineering polymerization-deficient F-actin oligomers that are able to act as F-actin binding protein scaffolds.
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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) | 0.000 | 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 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".