NumberReader
The younger version of this idea reads AlphaFold's confidence as four honest colours. NumberReader reads the real numbers. It loads a live AlphaFold model of human haemoglobin (the alpha subunit) and, for each region, asks you to commit a confidence guess before the number appears — then reveals the region's actual per-residue pLDDT, computed from the model itself, and the pairwise PAE. Everything runs locally; nothing about you is collected.
This is the tool. The numbers are not typed in by us — the game fetches the live model from the AlphaFold Database and computes each region's mean confidence from the model's own per-residue values, so you read the real AlphaFold output. Every region and the confidence bands are listed in full below (works without JavaScript).
Loading the live model… If it does not start, the full region guide below still works.
How to play. Press Start. A region of haemoglobin is highlighted in 3D. Commit how confident you think the model is there — 1 Very high, 2 Confident, 3 Low, 4 Very low — before the number shows. The real mean pLDDT for that region is then read off the model and scores your guess. A final round reads the real PAE, and one last question asks the thing that matters most: prediction, or experiment? Press Enter or Next to continue.
What the numbers mean: pLDDT and PAE
AlphaFold scores every residue from 0 to 100 for how sure it is of the local shape — a per-residue score called pLDDT. It is stored right in the model file (the B-factor column), which is where this game reads it. EMBL-EBI groups the score into four bands:
- Very high (pLDDT ≥ 90) — backbone and side chains usually both accurate
- Confident (70–90) — backbone usually right; some side chains may be off
- Low (50–70) — treat with caution — often flexible
- Very low (< 50) — should not be interpreted on its own
PAE (predicted aligned error, in ångströms) is different: it says how sure the model is about where two residues sit relative to each other. For a single tightly-folded domain like haemoglobin's alpha subunit, that number is small across the whole chain — the model is confident about the whole shape at once.
The regions this game reads
| Region | Residues | What it is |
|---|---|---|
| The very start (N-terminus) | 1–4 | The first few residues of the chain — a classic place a prediction is a little less sure, because chain ends are floppier and have fewer neighbours to pin them down. |
| The heme-pocket helices (E–F region) | 58–77 | The core helices that cradle the heme and its oxygen-carrying iron, including distal His58 and proximal His87 — tightly packed and well determined. |
| The folded globin core | 30–120 | The main body of the classic eight-helix globin fold — the compact, well-constrained kind of region AlphaFold predicts most confidently. |
| The very end (C-terminus) | 138–142 | The last few residues — like the N-terminus, a chain tail is less constrained, so its confidence often dips below the crisp core. |
Methods & about
The 3D model is fetched live from the AlphaFold Database (human haemoglobin subunit alpha, UniProt P69905) and coloured by pLDDT. Each region's confidence figure is computed in your browser from the model's own per-residue pLDDT (the mmCIF B-factor column); the PAE figure is read from AlphaFold's published PAE data. No number here is authored by us, and nothing is stored — your browser talks straight to the AlphaFold Database and computes the rest. Everything AlphaFold shows is a prediction, not an experiment: reading the real confidence numbers is exactly how you judge how far to trust each part of a predicted structure.
Want the qualitative, colour-based version for younger learners? Play VanishPoint. Want to drive any structure yourself? Open the free AlphaFold viewer. Everything we make is free and non-profit; learn more on the home page.