Na(+)/H(+) antiporter NhaA (nhaA) is a 388-residue protein from Escherichia coli (strain K12). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P13738.
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The mean pLDDT of this model is 89.3 (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 | 64% |
| 70 to 90 | Confident: backbone generally right | 31% |
| 50 to 70 | Low: treat with caution | 5% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
Na(+)/H(+) antiporter that extrudes sodium in exchange for external protons (PubMed:1645730, PubMed:23836890, PubMed:2839489, PubMed:7737413, PubMed:8019504, PubMed:8383669). Plays an important role in the regulation of intracellular pH, cellular Na(+) content and cell volume (PubMed:33129932). Catalyzes the exchange of 2 H(+) per Na(+) (PubMed:23836890, PubMed:8383669). This stoichiometry applies at both neutral and alkaline pH values (PubMed:8383669). In addition, can also transport lithium and is involved in lithium detoxification (PubMed:22915592, PubMed:27021484, PubMed:7737413, PubMed:8019504). Binding of the Li(+) and H(+) ligands to NhaA is coupled and antagonistic (PubMed:27021484)
Monomer (PubMed:17635927). Homodimer (PubMed:11258962, PubMed:15988517, PubMed:17635927, PubMed:19396973, PubMed:25422503). Under routine stress conditions, the monomeric form is fully functional (PubMed:17635927, PubMed:23836890). However, the dimeric form is much more efficient in conferring growth resistance under extreme stress conditions (PubMed:17635927)
Cell inner membrane
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 7S24 | X-ray | 2.2 Å | A=1-388 |
| 8PS0 | EM | 3.37 Å | A/B=1-388 |
| 1ZCD | X-ray | 3.45 Å | A/B=1-388 |
| 4ATV | X-ray | 3.5 Å | A/B/C/D=1-388 |
| 4AU5 | X-ray | 3.7 Å | A/B/C/D=1-388 |
| 3FI1 | EM | 7.0 Å | A=9-384 |
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