Sperm acrosome-associated protein 9 (SPACA9) is a 222-residue protein from Homo sapiens. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: Q96E40.
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The mean pLDDT of this model is 80.3 (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 | 67% |
| 70 to 90 | Confident: backbone generally right | 4% |
| 50 to 70 | Low: treat with caution | 7% |
| Below 50 | Very low: often disordered regions | 22% |
What pLDDT means and how to read it
Microtubule inner protein (MIP) part of the dynein-decorated doublet microtubules (DMTs) of multiciliated respiratory cells and the distal singlet microtubules of monoflagellated spermatozoa (PubMed:36191189). Forms an extensive interaction network cross-linking the lumen of axonemal doublet microtubules (By similarity)
Microtubule inner protein component of sperm flagellar doublet microtubules (PubMed:36191189). Interacts with CABP1 and CALR (By similarity). Interacts with INCA1 (By similarity). Interacts with microtubules (By similarity) (PubMed:36191189)
Cytoplasm, Cytoplasmic vesicle, secretory vesicle, acrosome, Cytoplasm, cytoskeleton, cilium basal body, Cytoplasm, cytoskeleton, flagellum axoneme, Cytoplasm, cytoskeleton, cilium axoneme, Nucleus
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 7UNG | EM | 3.6 Å | F0/F1/F2/F3/F4/F5/F6/F7/F8/G0/G1/G2/G3/G4/G5/G6/G7/G8/H0/H1/H2=1-222 |
| 8J07 | EM | 4.1 Å | 6A/6C/6E/6G/6I/6K/6L/6N/6O/6Q/6R/6T/6V=1-222 |
| 7UN1 | EM | 6.0 Å | A/B/C/D/E/F/G/H/I/J/K/L/M/N/O/P/Q/R/S/T/U/V/W/X/d/e/f/g/h/i=1-222 |
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