Discovery of Potent Pantothenamide Inhibitors of <i>Staphylococcus aureus</i> Pantothenate Kinase through a Minimal SAR Study: Inhibition Is Due to Trapping of the Product
Bibliographic record
Abstract
The potent antistaphylococcal activity of N -substituted pantothenamides (PanAms) has been shown to at least partially be due to the inhibition of Staphylococcus aureus ’s atypical type II pantothenate kinase ( Sa PanK II ), the first enzyme of coenzyme A biosynthesis. This mechanism of action follows from Sa PanK II having a binding mode for PanAms that is distinct from those of other PanKs. To dissect the molecular interactions responsible for PanAm inhibitory activity, we conducted a mini SAR study in tandem with the cocrystallization of Sa PanK II with two classic PanAms (N5-Pan and N7-Pan), culminating in the synthesis and characterization of two new PanAms, N -Pip-PanAm and MeO-N5-PanAm. The cocrystal structures showed that all of the PanAms are phosphorylated by Sa PanK II but remain bound at the active site; this occurs primarily through interactions with Tyr240′ and Thr172′. Kinetic analysis showed a strong correlation between k cat (slow PanAm turnover) and IC 50 (inhibition of pantothenate phosphorylation) values, suggesting that Sa PanK II inhibition occurs via a delay in product release. In-depth analysis of the PanAm-bound structures showed that the capacity for accepting a hydrogen bond from the amide of Thr172′ was a stronger determinant for PanAm potency than the capacity to π-stack with Tyr240′. The two new PanAms, N -Pip-PanAm and MeO-N5-PanAm, effectively combine both hydrogen bonding and hydrophobic interactions, resulting in the most potent Sa PanK II inhibition described to date. Taken together, our results are consistent with an inhibition mechanism wherein PanAms act as Sa PanK II substrates that remain bound upon phosphorylation. The phospho-PanAm– Sa PanK II interactions described herein may help future antistaphylococcal drug development.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".