Colicin E3 (ceaC) is a 551-residue protein from Escherichia coli. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P00646.
Explore in 3D Color by confidence AlphaFold DB UniProt
The mean pLDDT of this model is 85.0 (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 | 71% |
| 70 to 90 | Confident: backbone generally right | 14% |
| 50 to 70 | Low: treat with caution | 1% |
| Below 50 | Very low: often disordered regions | 15% |
What pLDDT means and how to read it
Colicins are polypeptide toxins produced by and active against E.coli and closely related bacteria (PubMed:3889348, PubMed:4930243, PubMed:4930244, PubMed:6295812). Cleaves 16S rRNA between adenosine-1492 and guanosine-1493 (E.coli 16S rRNA numbering), releasing a 49 nucleotide (nt) 'colicin' fragment (PubMed:20852642). Inactivates 70S ribosomes or 30S subunits by endonucleolytically cleaving 16S RNA at a specific site about 50 nt from its C-terminus (PubMed:4930243, PubMed:4930244, PubMed:782524). Produces 5'-OH-guanosine and a 2',3'-cyclic phosphate adenosine (PubMed:20852642, PubMed:4930244). Mixing a susceptible (e.g. strain K12 / A19) and colicin E3 producing strain results in total…
Native colicin E3 is a 1:1 complex of A chain and protein B (cognate immunity protein, Im3); protein A is 1,000-fold more active in inactivating ribosomes than the native complex (PubMed:336615). The cytotoxic fragment (residues 456-551, C95) forms a 1:1 complex with Im3 (PubMed:10986462). The receptor-binding (R) domain binds obliquely to its receptor BtuB without displacing BtuB's central…
Secreted
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 2B5U | X-ray | 2.3 Å | A/C=1-551 |
| 1E44 | X-ray | 2.4 Å | B=456-551 |
| 1UJW | X-ray | 2.75 Å | B=314-448 |
| 4UDM | X-ray | 2.96 Å | B=456-551 |
| 1JCH | X-ray | 3.02 Å | A/C=1-551 |
| 4V5K | X-ray | 3.2 Å | AY/CY=455-551 |
MolViewer loads the AlphaFold model straight from AlphaFold DB into your browser. Show it as a cartoon, color by pLDDT, measure distances and angles, and load a PDB structure next to it to compare.