Tubulin beta-4B chain (TUBB4B) is a 445-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P68371.
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The mean pLDDT of this model is 92.3 (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 | 12% |
| 50 to 70 | Low: treat with caution | 3% |
| Below 50 | Very low: often disordered regions | 1% |
What pLDDT means and how to read it
Tubulin is the major constituent of microtubules, a cylinder consisting of laterally associated linear protofilaments composed of alpha- and beta-tubulin heterodimers. Microtubules grow by the addition of GTP-tubulin dimers to the microtubule end, where a stabilizing cap forms. Below the cap, tubulin dimers are in GDP-bound state, owing to GTPase activity of alpha-tubulin
Dimer of alpha and beta chains. A typical microtubule is a hollow water-filled tube with an outer diameter of 25 nm and an inner diameter of 15 nM. Alpha-beta heterodimers associate head-to-tail to form protofilaments running lengthwise along the microtubule wall with the beta-tubulin subunit facing the microtubule plus end conferring a structural polarity. Microtubules usually have 13…
Cytoplasm, cytoskeleton, Cytoplasm, cytoskeleton, flagellum axoneme
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 8SH7 | EM | 2.8 Å | B=1-445 |
| 7UNG | EM | 3.6 Å | AB/AD/AF/AH/AJ/AL/BB/BD/BF/BH/BJ/BL/CB/CD/CF/CH/CJ/CL/DB/DD/DF/DH/DJ/DL/EB/ED/EF/EH/EJ/EL=1-445 |
| 8J07 | EM | 4.1 Å | AB/AD/AF/AH/AJ/AL/AN/AP/AR/AT/AV/AX/BB/BD/BF/BH/BJ/BL/BN/BP/BR/BT/BV/BX/CB/CD/CF/CH/CJ/CL=1-445 |
| 7UN1 | EM | 6.0 Å | AB/AD/AF/BA/BD/BF/CB/CD/CF/DB/DD/DF/EB/ED/EF/FD/FF/FH/GD/GF/GH/HD/HF/HH/ID/IF/IH/JD/JF/KD=1-445 |
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