Measurement of <sup>13</sup>C<sup>α</sup>−<sup>13</sup>C<sup>β</sup> Dipolar Couplings in <sup>15</sup>N,<sup>13</sup>C,<sup>2</sup>H-Labeled Proteins: Application to Domain Orientation in Maltose Binding Protein
Bibliographic record
Abstract
TROSY-based HN(CO)CA 2D and 3D pulse schemes are presented for measurement of (13)C(alpha)-(13)C(beta) dipolar couplings in high molecular weight (15)N,(13)C,(2)H-labeled proteins. In one approach, (13)C(alpha)-(13)C(beta) dipolar couplings are obtained directly from the time modulation of cross-peak intensities in a set of 2D (15)N-(1)HN correlated spectra recorded in both the presence and absence of aligning media. In a second approach 3D data sets are recorded with (13)C(alpha)-(13)C(beta) couplings encoded in a frequency dimension. The utility of the experiments is demonstrated with an application to an (15)N,(13)C,(2)H-labeled sample of the ligand free form of maltose binding protein. A comparison of experimental dipolar couplings with those predicted from the X-ray structure of the apo form of this two-domain protein establishes that the relative orientation of the domains in solution and in the crystal state are very similar. This is in contrast to the situation for maltose binding protein in complex with beta-cyclodextrin where the solution structure can be generated from the crystal state via a 11 degrees domain closure.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".