Regulator of nonsense transcripts 3B (UPF3B) is a 483-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q9BZI7.
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The mean pLDDT of this model is 65.8 (low 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 | 18% |
| 70 to 90 | Confident: backbone generally right | 36% |
| 50 to 70 | Low: treat with caution | 11% |
| Below 50 | Very low: often disordered regions | 35% |
What pLDDT means and how to read it
Involved in nonsense-mediated decay (NMD) of mRNAs containing premature stop codons by associating with the nuclear exon junction complex (EJC) and serving as link between the EJC core and NMD machinery. Recruits UPF2 at the cytoplasmic side of the nuclear envelope and the subsequent formation of an UPF1-UPF2-UPF3 surveillance complex (including UPF1 bound to release factors at the stalled ribosome) is believed to activate NMD. In cooperation with UPF2 stimulates both ATPase and RNA helicase activities of UPF1. Binds spliced mRNA upstream of exon-exon junctions. In vitro, stimulates translation; the function is independent of association with UPF2 and components of the EJC core
Forms a trimeric UPF complex where UPF2 bridges UPF1 and UPF3B; UPF2 contacts the N-terminal CH-rich domain of UPF1 and the N-terminus of UPF3B (PubMed:18066079). The trimeric UPF complex interacts with the EJC core complex (PubMed:18066079). Found in a post-splicing messenger ribonucleoprotein (mRNP) complex. Core component of the mRNA splicing-dependent exon junction complex (EJC); the core…
Nucleus, Cytoplasm
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 1UW4 | X-ray | 1.95 Å | A/C=50-140 |
| 7NWU | X-ray | 2.6 Å | A/C/E/G=49-170 |
| 2XB2 | X-ray | 3.4 Å | G/U=424-483 |
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