Phosphoenolpyruvate-protein phosphotransferase (ptsI) is a 575-residue protein from Escherichia coli (strain K12). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P08839.
Explore in 3D Color by confidence AlphaFold DB UniProt
The mean pLDDT of this model is 90.3 (very high overall). pLDDT is AlphaFold's per-residue confidence score from 0 to 100. In MolViewer, choose the B-factor color scheme to color the model by pLDDT, because AlphaFold stores it in the B-factor column.
| pLDDT band | Meaning | Share of residues |
|---|---|---|
| Above 90 | Very high: backbone and side chains are usually accurate | 61% |
| 70 to 90 | Confident: backbone generally right | 36% |
| 50 to 70 | Low: treat with caution | 2% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
General (non sugar-specific) component of the phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS). This major carbohydrate active-transport system catalyzes the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. Enzyme I transfers the phosphoryl group from phosphoenolpyruvate (PEP) to the phosphoryl carrier protein (HPr) (PubMed:12705838, PubMed:17053069, PubMed:7876255). Can also use (Z)-3-fluoro-PEP (ZFPEP), (Z)-3-methyl-PEP (ZMePEP), (Z)-3-chloro-PEP (ZClPEP) and (E)-3-chloro-PEP (EClPEP) as alternative phosphoryl donors (PubMed:12705838)
Homodimer (PubMed:12705838, PubMed:17053069). Interacts with the pole-localizer protein TmaR (PubMed:33376208). Binding to TmaR is reversible as long as TmaR can get phosphorylated, whereas binding to non-phosphorylated TmaR is very strong and shifts the equilibrium toward binding (PubMed:33376208)
Cytoplasm
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6V9K | X-ray | 1.9 Å | A/B=261-575 |
| 1ZYM | X-ray | 2.5 Å | A/B=1-258 |
| 2HWG | X-ray | 2.7 Å | A/B=1-575 |
| 6VU0 | X-ray | 3.5 Å | A/B=261-575 |
| 1EZA | NMR | A=1-258 | |
| 1EZB | NMR | A=1-258 | |
| 1EZC | NMR | A=1-258 | |
| 1EZD | NMR | A=1-258 | |
| 2EZA | NMR | A=1-258 | |
| 2EZB | NMR | A=1-258 | |
| 2EZC | NMR | A=1-258 | |
| 2KX9 | Other | A/B=1-573 | |
| 2L5H | Other | A/B=1-573 | |
| 2MP0 | NMR | A=1-258 | |
| 2N5T | Other | A/B=1-575 | |
| 2XDF | Other | A/B=1-573 | |
| 3EZA | NMR | A=1-249 | |
| 3EZB | NMR | A=1-259 | |
| 3EZE | NMR | A=1-258 |
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