Recombinant Synechococcus sp. ATP synthase subunit alpha (atpA), partial
Description
Functional Significance in ATP Synthesis
The α-subunit (AtpA) is essential for F₀F₁ ATP synthase activity, coordinating proton translocation and ATP production. Mutational studies highlight its role in stress tolerance:
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C252Y Mutation: A single amino acid substitution (Cysteine → Tyrosine) at position 252 enhances ATP synthase activity under heat stress. This mutation increases AtpA protein stability and intracellular ATP levels, improving photosynthetic efficiency and glycogen accumulation .
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Mechanistic Insights: The mutation alters redox regulation and protein-protein interactions, potentially stabilizing the ATP synthase complex under adverse conditions .
Table 2: Impact of C252Y Mutation on ATP Synthase Activity
| Parameter | Synechococcus 7942 (Wild Type) | Synechococcus 7942-C252Y |
|---|---|---|
| ATP Synthase Activity | 773 nmol·min⁻¹·mg Chl⁻¹ | Elevated under stress |
| AtpA Protein Levels | Basal levels | Increased under stress |
| Intracellular ATP | Moderate | ~30% higher under stress |
Stress Tolerance and Photosynthetic Efficiency
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Heat Stress: The C252Y mutation in AtpA elevates ATP synthesis rates and glycogen storage, enabling survival under high temperatures (e.g., 45°C) .
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High Light Stress: Enhanced ATP production supports D1 protein repair in photosystem II, reducing photoinhibition .
Metabolic Engineering
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Strain Optimization: Incorporating the C252Y allele into Synechococcus 7942 improves growth rates and photosynthetic productivity, demonstrating its potential for biofuel production .
Table 3: Comparative Growth Rates of Engineered Strains
| Strain | Doubling Time (Hours) | Photosynthetic Productivity |
|---|---|---|
| Synechococcus 7942 | 6.8 | Basal |
| Synechococcus 7942-C252Y | Reduced (~2.3 when combined with other SNPs) | Doubled |
Comparative Genomics and Evolutionary Context
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Conservation: AtpA is highly conserved across cyanobacteria, with 88.95% of species retaining a tyrosine at position 252 (unlike Synechococcus 7942’s cysteine) .
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Phylogenetic Clustering: Synechococcus strains with the C252Y mutation cluster separately from marine species, suggesting freshwater adaptation .
Table 4: AtpA Conservation Across Cyanobacteria
| Species | AtpA Position 252 Residue | Habitat Preference |
|---|---|---|
| Synechococcus 7942 | Cysteine (C) | Freshwater |
| Synechococcus 2973 | Tyrosine (Y) | Freshwater |
| Prochlorococcus spp. | Tyrosine (Y) | Marine/Brackish |
Site-Saturation Mutagenesis
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Method: Primers targeting AtpA’s cysteine 252 were used to generate mutants (e.g., C252H, C252F, C252W) via CRISPR/Cpf1 editing .
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Outcome: All substitutions improved ATP synthase activity, confirming the residue’s critical role .
Transcriptomic Analysis
Product Specs
Target Background
KEGG: syx:SynWH7803_2017
STRING: 32051.SynWH7803_2017
