Histone H2A (His2A) is a 124-residue protein from Drosophila melanogaster. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P84051.
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The mean pLDDT of this model is 93.1 (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 | 83% |
| 70 to 90 | Confident: backbone generally right | 9% |
| 50 to 70 | Low: treat with caution | 8% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Involved in recruitment of Parp1 to chromatin and regulates its activity; the N-terminal tail inhibits histone H4-dependent activation of Parp1 (PubMed:17827147, PubMed:24508391)
The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. The octamer wraps approximately 147 bp of DNA. Interacts with Parp1 (via C-terminus); the interaction is direct and regulates Parp1 enzymatic activity (PubMed:17827147)
Nucleus, Chromosome
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 9ZQB | EM | 2.1 Å | A/B=1-124 |
| 2NQB | X-ray | 2.3 Å | C/G=2-124 |
| 9ZQC | EM | 2.37 Å | A/B=1-124 |
| 2PYO | X-ray | 2.43 Å | C/G=2-121 |
| 8UX1 | EM | 2.5 Å | C/G=1-124 |
| 8PP7 | EM | 2.91 Å | C/G=2-124 |
| 6DZT | EM | 2.99 Å | C/G=1-124 |
| 8PP6 | EM | 3.18 Å | C/G=2-124 |
| 9ZQA | EM | 3.28 Å | A/B=1-124 |
| 9MU4 | EM | 3.29 Å | c/g=14-119 |
| 9ZQ9 | EM | 3.3 Å | A/B=1-124 |
| 4QLC | X-ray | 3.5 Å | C/G=2-124 |
| 4X23 | X-ray | 3.5 Å | C/G/M/Q=16-117 |
| 7XYF | EM | 3.8 Å | C/G=14-119 |
| 6PWE | EM | 3.95 Å | C/G=1-124 |
| 6PWF | EM | 4.07 Å | C/G=1-124 |
| 7XYG | EM | 5.4 Å | C/G=2-124 |
| 5WCU | X-ray | 5.53 Å | C/G/M/Q=15-118 |
| 9MU5 | EM | 6.3 Å | g=14-118 |
| 9MU9 | EM | 7.8 Å | c/g=14-119 |
Showing 20 of 21 experimental structures (best resolution first).
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