Inward rectifier potassium channel 2 (KCNJ2) is a 427-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P63252.
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The mean pLDDT of this model is 81.6 (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 | 66% |
| 70 to 90 | Confident: backbone generally right | 13% |
| 50 to 70 | Low: treat with caution | 3% |
| Below 50 | Very low: often disordered regions | 19% |
What pLDDT means and how to read it
Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it (PubMed:36149965, PubMed:7590287, PubMed:9490857). Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages (PubMed:7590287, PubMed:7696590). The inward rectification is mainly due to the blockage of outward current by internal magnesium (PubMed:9490857). Can be blocked by extracellular barium or cesium (PubMed:7590287, PubMed:7696590). Probably participates in establishing action potential waveform and excitability of…
Homotetramer (PubMed:36149965, PubMed:16571646). Homomultimeric and heteromultimeric association with KCNJ4/Kir2.3 (PubMed:12032359). Can form heteromeric channels with Kir2.6/KCNJ18 (PubMed:21209095). Associates, via its PDZ-recognition domain, with a complex containing LIN7A, LIN7B, LIN7C, DLG1, CASK and APBA1 (By similarity)
Cell membrane, Cell membrane, sarcolemma, T-tubule
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6SPZ | X-ray | 2.08 Å | P/Q=422-427 |
| 7ZDZ | EM | 4.3 Å | A/B/C/D=1-427 |
| 8QQL | EM | 6.0 Å | A/B/C/D=46-362 |
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