Cohesin subunit SA-2 (STAG2) is a 1231-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q8N3U4.
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The mean pLDDT of this model is 79.5 (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 | 63% |
| 70 to 90 | Confident: backbone generally right | 13% |
| 50 to 70 | Low: treat with caution | 2% |
| Below 50 | Very low: often disordered regions | 22% |
What pLDDT means and how to read it
Component of cohesin complex, a complex required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At anaphase, the complex is cleaved and dissociates from chromatin, allowing sister chromatids to segregate. The cohesin complex may also play a role in spindle pole assembly during mitosis
Interacts directly with RAD21 in cohesin complex. Cohesin complexes are composed of a heterodimer between a SMC1 protein (SMC1A or SMC1B) and SMC3, which are attached via their hinge domain, and RAD21 which link them at their heads, and one STAG protein (STAG1, STAG2 or STAG3). In cohesin complexes, STAG2 is mutually exclusive with STAG1 and STAG3
Nucleus, Chromosome, Chromosome, centromere
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 6QNX | X-ray | 2.7 Å | A=80-1060 |
| 4PJW | X-ray | 2.85 Å | A=80-1060 |
| 9HMV | EM | 2.9 Å | A=1-1231 |
| 4PK7 | X-ray | 2.95 Å | A=80-1060 |
| 4PJU | X-ray | 3.05 Å | A=80-1060 |
| 9EP3 | X-ray | 3.08 Å | A=80-1060 |
| 7ZJS | X-ray | 3.24 Å | A/C=1-1231 |
| 9HMS | EM | 3.4 Å | A=1-1231 |
| 8K4D | X-ray | 3.52 Å | A=81-1060 |
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