Guanine nucleotide-binding protein G(i) subunit alpha-3 (GNAI3) is a 354-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P08754.
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The mean pLDDT of this model is 93.8 (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 | 87% |
| 70 to 90 | Confident: backbone generally right | 10% |
| 50 to 70 | Low: treat with caution | 2% |
| Below 50 | Very low: often disordered regions | 1% |
What pLDDT means and how to read it
Heterotrimeric guanine nucleotide-binding proteins (G proteins) function as transducers downstream of G protein-coupled receptors (GPCRs) in numerous signaling cascades. The alpha chain contains the guanine nucleotide binding site and alternates between an active, GTP-bound state and an inactive, GDP-bound state. Signaling by an activated GPCR promotes GDP release and GTP binding. The alpha subunit has a low GTPase activity that converts bound GTP to GDP, thereby terminating the signal (By similarity). Both GDP release and GTP hydrolysis are modulated by numerous regulatory proteins (PubMed:18434541, PubMed:19478087, PubMed:8774883). Signaling is mediated via effector proteins, such as…
Heterotrimeric G proteins are composed of 3 units; alpha, beta and gamma. The alpha subunit contains the guanine nucleotide binding site (By similarity). GTP binding causes dissociation of the heterotrimer, liberating the individual subunits so that they can interact with downstream effector proteins. Forms a complex with CCDC88A/GIV and EGFR which leads to enhanced EGFR signaling and triggering…
Cytoplasm, Cell membrane, Cytoplasm, cytoskeleton, microtubule organizing center, centrosome
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 2ODE | X-ray | 1.9 Å | A/C=4-350 |
| 8YK0 | EM | 2.4 Å | C=6-354 |
| 7T10 | EM | 2.5 Å | A=1-354 |
| 9VJ6 | EM | 2.62 Å | B=1-354 |
| 7T11 | EM | 2.7 Å | A=1-354 |
| 9VJF | EM | 2.7 Å | B=1-354 |
| 2IHB | X-ray | 2.71 Å | A=32-354 |
| 2V4Z | X-ray | 2.8 Å | A=4-350 |
| 7KH0 | EM | 2.8 Å | A=2-19 |
| 4G5O | X-ray | 2.9 Å | A/B/C/D=25-354 |
| 7RGP | EM | 2.9 Å | A=4-19 |
| 8K9L | EM | 3.05 Å | A=1-354 |
| 8SZH | EM | 3.1 Å | C=1-354 |
| 7RA3 | EM | 3.24 Å | A=1-19 |
| 8GY7 | EM | 3.3 Å | A=1-20, A=61-181, A=229-242 |
| 9WXM | EM | 3.3 Å | A=1-354 |
| 8OY1 | X-ray | 3.34 Å | A=31-350 |
| 8JD6 | EM | 3.4 Å | A=1-354 |
| 4G5R | X-ray | 3.48 Å | A/B/C/D=25-354 |
| 8SZI | EM | 3.5 Å | C=1-354 |
Showing 20 of 26 experimental structures (best resolution first).
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