Impact of Salt Concentration and pH on Surface Charged Residues: Controlling Protein Association Pathways in Carboxylesterase EstGtA2
Bibliographic record
Abstract
BACKGROUND: Understanding the relationship between enzymatic stability and the amino acid sequence encoding carboxylesterases is of utmost importance. OBJECTIVES: Here we thoroughly characterized the behavior of the carboxylesterase EstGtA2 from Geobacillus thermodenitrificans during thermal denaturation at different pH with various salt concentrations. METHOD: EstGtA2 was characterized by circular dichroism regarding conformation and thermal stability, by dynamic light scattering for detection of association/aggregation, by enzymatic assays for activity and by monitoring the impact of heat treatments on activity. RESULTS: Our investigation revealed a particular dependence between aggregation/association and preservation of secondary structures upon heating in EstGtA2. At pH 7, 8 and 9, depending on salt concentration, a folded but non-native associated state characterised by an apparent particle size of 300 nm resisted secondary structure unfolding up to 95°C. CONCLUSION: The paths leading to various aggregative states were found to be controlled by pH (depending on proximity to pI) and to a lesser extent, ionic strength, suggesting that ionic interactions at the surface of the protein are responsible for behavior of EstGtA2. The various paths available to EstGtA2 could be important for protection of Geobacillus termodenitrificans when exposed to heat stress. The understanding and/or control of these paths would allow for optimal use of EstGtA2 in industrial processes.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".