Actin-1 (ACT1) is a 376-residue protein from Plasmodium falciparum (isolate 3D7). This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q8I4X0.
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The mean pLDDT of this model is 95.2 (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 | 93% |
| 70 to 90 | Confident: backbone generally right | 4% |
| 50 to 70 | Low: treat with caution | 2% |
| Below 50 | Very low: often disordered regions | 1% |
What pLDDT means and how to read it
Actin is a highly conserved protein that polymerizes to produce filaments that form cross-linked networks in the cytoplasm (PubMed:24743229, PubMed:28923924, PubMed:31199804). Polymerizes into shorter and less stable actin filaments compared to ACT2/actin-2; this is thought to facilitate gliding motility and host cell invasion (PubMed:24743229, PubMed:28923924). Has ATPase activity (PubMed:24743229, PubMed:31199804). ATP hydrolysis leads to the formation of a stable intermediate ADP-inorganic phosphate (Pi) actin, which is followed by the release of Pi (Probable). ATP hydrolysis affects filament stability; ADP-bound actin depolymerizes much faster than ATP- or ADP-Pi-bound actin…
Monomer (G-actin) (PubMed:24743229). Oligomer (F-actin) (PubMed:24743229, PubMed:28923924). Polymerization of globular actin (G-actin) leads to a structural filament (F-actin) in the form of a two-stranded helix (PubMed:24743229, PubMed:28923924). Unlike for mammalian monomeric actin, parasite monomeric actin is able to induce oligomerization in the presence of ATP or ADP (PubMed:24743229).…
Cytoplasm, Nucleus, Cytoplasm, cytoskeleton
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6I4E | X-ray | 1.22 Å | A=1-376 |
| 6I4D | X-ray | 1.24 Å | A=1-376 |
| 4CBU | X-ray | 1.3 Å | A=1-376 |
| 5MVV | X-ray | 1.4 Å | A=1-376 |
| 6I4H | X-ray | 1.4 Å | A=1-376 |
| 6I4F | X-ray | 1.5 Å | A=1-376 |
| 6I4J | X-ray | 1.5 Å | A=1-376 |
| 6I4K | X-ray | 1.83 Å | A=1-376 |
| 6I4L | X-ray | 1.83 Å | A=1-376 |
| 6I4I | X-ray | 1.9 Å | A=1-376 |
| 6I4G | X-ray | 2.0 Å | A/B=1-376 |
| 6TU4 | EM | 2.6 Å | A/B/C/D/F=1-376 |
| 6TU7 | EM | 3.1 Å | BP1/CP1/DP1/EP1=1-376 |
| 7ALN | EM | 3.77 Å | A/B/C/D/E=1-376 |
| 5OGW | EM | 3.8 Å | A/B/C/D/E=1-376 |
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