Sodium channel protein type 4 subunit alpha (SCN4A) is a 1836-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P35499.
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The mean pLDDT of this model is 72.4 (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 | 19% |
| 70 to 90 | Confident: backbone generally right | 49% |
| 50 to 70 | Low: treat with caution | 14% |
| Below 50 | Very low: often disordered regions | 18% |
What pLDDT means and how to read it
Pore-forming subunit of Nav1.4, a voltage-gated sodium (Nav) channel that directly mediates the depolarizing phase of action potentials in excitable membranes. Navs, also called VGSCs (voltage-gated sodium channels) or VDSCs (voltage-dependent sodium channels), operate by switching between closed and open conformations depending on the voltage difference across the membrane. In the open conformation they allow Na(+) ions to selectively pass through the pore, along their electrochemical gradient. The influx of Na+ ions provokes membrane depolarization, initiating the propagation of electrical signals throughout cells and tissues (PubMed:12766226, PubMed:15318338, PubMed:16890191,…
The Nav1.4 voltage-gated sodium channel consists of an ion-conducting alpha subunit SCN4A which is functional on its own and a regulatory beta subunit SCN1B (PubMed:29992740, PubMed:30190309). SCN1B strongly enhances the presence of SCN4A at the cell surface (PubMed:29992740). SCN1B is also required for rapid channel inactivation and recovery after inactivation. It prevents the decrease of…
Cell membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6MBA | X-ray | 1.8 Å | A=1599-1764 |
| 6AGF | EM | 3.2 Å | A=1-1836 |
| 6MC9 | X-ray | 3.3 Å | A=1599-1754 |
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