Non-linear intramolecular interactions and voltage sensitivity of a KV1 family potassium channel from<i>Polyorchis penicillatus</i>(Eschscholtz 1829)
Bibliographic record
Abstract
Voltage sensitivity of voltage-gated potassium channels (VKCs) is a primary factor in shaping action potentials in excitable cells. Variation in the amino acid sequence of the channel proteins is responsible for differences in the voltage range over which the channel opens. Thus, understanding how changes in voltage sensitivity are effected by changes in channel protein sequence illuminates the functional evolution of excitability. The K(V)1-family channel jShak1, from the jellyfish Polyorchis penicillatus, differs from most other K(V)1 channels in ways that are useful for studying the problem of how voltage sensitivity is related to channel sequence. We assessed the contributions of changes in sequence of the S4, voltage sensing, helix and changes in one asparagine residue in the S2 helix, to the relative stability of the open and closed states of the channel. Mutation of the neutral S2 residue (Asn227) to glutamate stabilized the open conformation of the channel. Different modifications of charge and length in S4 favoured either the closed conformation or the open conformation. The interactions between pairs of mutations revealed that some of the S4 mutations alter the conformation of the voltage-sensing domain such that the S4 helix is constrained to be closer to the S2 helix than in the wild-type conformation. These results, taken in conjunction with three-dimensional models of the channel, identify intra-molecular interactions that control the balance between open and closed states. These interactions are likely to be relevant to understanding the functional characteristics of members of this channel family from other organisms.
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 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) | 0.001 | 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".