Vitamin B12 transporter BtuB (btuB) is a 614-residue protein from Escherichia coli (strain K12). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P06129.
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The mean pLDDT of this model is 91.3 (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 | 81% |
| 70 to 90 | Confident: backbone generally right | 14% |
| 50 to 70 | Low: treat with caution | 2% |
| Below 50 | Very low: often disordered regions | 4% |
What pLDDT means and how to read it
Involved in the active translocation of vitamin B12 (cyanocobalamin) across the outer membrane to the periplasmic space (PubMed:4579869). It derives its energy for transport by interacting with the trans-periplasmic membrane protein TonB
Interacts with TonB
Cell outer membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 2GUF | X-ray | 1.95 Å | A=21-614 |
| 1NQE | X-ray | 2.0 Å | A=21-614 |
| 2GSK | X-ray | 2.1 Å | A=25-614 |
| 3RGN | X-ray | 2.3 Å | A=21-614 |
| 3M8B | X-ray | 2.44 Å | A=21-614 |
| 3M8D | X-ray | 2.44 Å | A=21-614 |
| 3RGM | X-ray | 2.6 Å | A=21-614 |
| 1NQF | X-ray | 2.7 Å | A=21-614 |
| 1UJW | X-ray | 2.75 Å | A=21-614 |
| 1NQH | X-ray | 3.1 Å | A=21-614 |
| 1NQG | X-ray | 3.31 Å | A=21-614 |
| 2YSU | X-ray | 3.5 Å | A=21-614 |
| 7NSU | EM | 4.7 Å | F=21-614 |
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