Interaction of acyl carrier protein with enzyme partners: insights from fluorescence
Bibliographic record
Abstract
Acyl carrier protein (ACP) is a natively unfolded protein that undergoes reversible conformational change as it shuttles fatty acyl groups among a variety of enzymes in the synthesis of bacterial lipids and other products. Folding of ACP upon divalent cation binding or fatty acylation has previously been monitored by intrinsic Trp fluorescence of ACP mutant L46W. In the present study, we found that interaction with UDP‐GlcNAc acyltransferase (LpxA) produced a large fluorescence blue shift of L46W, indicating that ACP also folds upon LpxA binding. LpxA (but not Mg 2+ ) caused a smaller blue shift of mutant A45W, suggesting that this residue may be involved directly in enzyme interaction. Based on Trp fluorescence, LpxA interacted preferentially with holo‐ vs apo‐ACP, while the opposite was true for holo‐ACP synthase (AcpS). Titration with LpxA also caused a 2‐fold increase in fluorescence intensity of ACP labeled with AEDANS at the phosphopantetheine sulfhydryl group (apparent K d of 2 μM). Addition of Mg 2+ reversed this LpxA‐induced fluorescence increase, suggesting that binding of LpxA and divalent cations to ACP results in different phosphopantetheine environments. Fluorescence thus provides insight into the binding and conformational changes that accompany ACP interaction with partner enzymes ( supported by CIHR and NSERC ).
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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 | 0.001 |
| Open science | 0.000 | 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".