Characterization of de novo four‐helix bundles by molecular dynamics simulations
Bibliographic record
Abstract
We have investigated the structure and dynamics of three cavitand-based four-helix bundles (caviteins) by computer simulation. In these systems, designed de novo, each of the four helices contain the identical basis sequence EELLKKLEELLKKG (N1). Each cavitein consists of a rigid macrocycle (cavitand) with four aryl linkages, to each of which is connected an N1 peptide by means of a linker peptide. The three caviteins studied here differ only in the linker peptide, which consist of one, two, or three glycine residues. Previous experimental work has shown that these systems exhibit very different behavior in terms of stability and oligomerization states despite the small differences in the linker peptide. Given that to date no three-dimensional structure is available for these caviteins, we have undertaken a series of molecular dynamics (MD) simulations in explicit water to try to rationalize the large differences in the experimentally observed behavior of these systems. Our results provide insight, for the first time, into why and how the cavitein with a single glycine linker forms dimers. In addition, our results indicate why although the two- and three-glycine-linked caviteins have similar stabilities, they have different native-like characteristics: the cavitein with three glycines can form a supercoiled helix, whereas the one with two glycines cannot. These findings may provide a useful guide in the rational de novo design of novel proteins with finely tunable structures and functions in the future.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".