Ribulose bisphosphate carboxylase small subunit, chloroplastic 1 (RBCS1) is a 123-residue protein from Spinacia oleracea. This is its AlphaFold structure prediction, created 1 Aug 2025. UniProt accession: P00870.
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The mean pLDDT of this model is 94.6 (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 | 89% |
| 70 to 90 | Confident: backbone generally right | 11% |
| 50 to 70 | Low: treat with caution | 0% |
| Below 50 | Very low: often disordered regions | 0% |
What pLDDT means and how to read it
RuBisCO catalyzes two reactions: the carboxylation of D-ribulose 1,5-bisphosphate, the primary event in carbon dioxide fixation, as well as the oxidative fragmentation of the pentose substrate. Both reactions occur simultaneously and in competition at the same active site. Although the small subunit is not catalytic it is essential for maximal activity
Heterohexadecamer of 8 large and 8 small subunits
Plastid, chloroplast
Compare the prediction with experimentally determined structures of the same protein:
| PDB ID | Method | Resolution | Chains and residues |
|---|---|---|---|
| 8RUC | X-ray | 1.6 Å | I/J/K/L=1-123 |
| 1RXO | X-ray | 2.2 Å | C/F/I/S=1-123 |
| 1RBO | X-ray | 2.3 Å | C/F/I/S=1-123 |
| 1RCO | X-ray | 2.3 Å | C/F/I/M/P/S/T/W=1-123 |
| 1RCX | X-ray | 2.4 Å | C/F/I/M/P/S/T/W=1-123 |
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