Lactose permease (lacY) is a 417-residue protein from Escherichia coli (strain K12). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P02920.
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The mean pLDDT of this model is 82.4 (confident 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 | 22% |
| 70 to 90 | Confident: backbone generally right | 67% |
| 50 to 70 | Low: treat with caution | 7% |
| Below 50 | Very low: often disordered regions | 5% |
What pLDDT means and how to read it
Responsible for transport of beta-galactosides into the cell, with the concomitant import of a proton (symport system). Can transport lactose, melibiose, the synthetic disaccharide lactulose or the analog methyl-1-thio-beta,D-galactopyranoside (TMG), but not sucrose or fructose (PubMed:18177889, PubMed:1848449, PubMed:22106930, PubMed:7000781, PubMed:7028742). The substrate specificity is directed toward the galactopyranosyl moiety of the substrate (PubMed:22106930)
Monomer
Cell inner membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 9XOU | EM | 2.5 Å | G/H/I=1-417 |
| 6VBG | X-ray | 2.8 Å | A/B=1-417 |
| 2CFQ | X-ray | 2.95 Å | A=1-417 |
| 8YA0 | EM | 2.97 Å | B=316-332 |
| 6C9W | X-ray | 3.0 Å | A=1-417 |
| 8YA3 | EM | 3.27 Å | B=315-334 |
| 8Y9Y | EM | 3.29 Å | B=315-334 |
| 2CFP | X-ray | 3.3 Å | A=1-417 |
| 5GXB | X-ray | 3.3 Å | A=1-417 |
| 4ZYR | X-ray | 3.31 Å | A/B=1-417 |
| 2Y5Y | X-ray | 3.38 Å | A/B=1-417 |
| 1PV6 | X-ray | 3.5 Å | A/B=1-417 |
| 1PV7 | X-ray | 3.6 Å | A/B=1-417 |
| 2V8N | X-ray | 3.6 Å | A/B=1-417 |
| 8YA2 | EM | 3.84 Å | B=315-334 |
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