pH-gated potassium channel KcsA (kcsA) is a 160-residue protein from Streptomyces lividans. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P0A334.
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The mean pLDDT of this model is 89.6 (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 | 78% |
| 70 to 90 | Confident: backbone generally right | 13% |
| 50 to 70 | Low: treat with caution | 8% |
| Below 50 | Very low: often disordered regions | 2% |
What pLDDT means and how to read it
Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+)
Homotetramer
Cell membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 2IH3 | X-ray | 1.72 Å | C=3-122 |
| 1R3J | X-ray | 1.9 Å | C=1-124 |
| 2HVK | X-ray | 1.9 Å | C=1-124 |
| 1K4C | X-ray | 2.0 Å | C=1-124 |
| 2P7T | X-ray | 2.05 Å | C=22-124 |
| 6PA0 | X-ray | 2.05 Å | C=22-124 |
| 4MSW | X-ray | 2.06 Å | C=22-124 |
| 6NFU | X-ray | 2.09 Å | C=22-124 |
| 6NFV | X-ray | 2.13 Å | C=22-124 |
| 2H8P | X-ray | 2.25 Å | C=22-122 |
| 5VK6 | X-ray | 2.25 Å | C=26-121 |
| 5VKH | X-ray | 2.25 Å | C=22-124 |
| 1K4D | X-ray | 2.3 Å | C=1-124 |
| 3OR7 | X-ray | 2.3 Å | C=22-124 |
| 5EBL | X-ray | 2.3 Å | C=1-125 |
| 5EBW | X-ray | 2.3 Å | C=1-123 |
| 5EC2 | X-ray | 2.3 Å | C=1-125 |
| 6W0I | X-ray | 2.33 Å | C=22-124 |
| 5VKE | X-ray | 2.37 Å | C=26-121 |
| 1R3I | X-ray | 2.4 Å | C=1-124 |
Showing 20 of 89 experimental structures (best resolution first).
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