Recombinant Buchnera aphidicola subsp. Acyrthosiphon pisum Superoxide dismutase [Mn] (sodA)
Description
Molecular Characterization of SodA
SodA belongs to the manganese-dependent superoxide dismutase family, which is essential for neutralizing reactive oxygen species (ROS) in prokaryotes. In Buchnera aphidicola, SodA is encoded by the sodA gene, a component of the bacterium’s reduced genome. Key features include:
-
Gene Locus: Located within the Buchnera chromosome, adjacent to stress-response operons .
-
Protein Structure: Predicted molecular weight of ~23 kDa, with a conserved Mn-binding motif (DVWEHAYY) .
Table 1: Comparative Genomic Features of Buchnera SodA
| Property | B. aphidicola APS (Pea Aphid) | Other Buchnera Strains |
|---|---|---|
| Genome Size (bp) | 652,115 | 412,404–645,850 |
| sodA Gene Length (bp) | ~600 | ~600–615 |
| GC Content (%) | 26.24 | 20.2–26.3 |
| Codon Adaptation Index | 0.32 | 0.28–0.35 |
Recombinant Production and Purification
Recombinant SodA is typically expressed in Escherichia coli using plasmid vectors, fused with affinity tags (e.g., His-tag) for purification . Key steps include:
-
Cloning: The sodA gene is amplified from Buchnera genomic DNA and inserted into an expression vector (e.g., pET-28a).
-
Expression: Induced with IPTG, yielding soluble protein in the cytoplasmic fraction .
-
Purification: Nickel-affinity chromatography achieves >90% purity, confirmed by SDS-PAGE .
Table 2: Expression and Purification Metrics
| Parameter | Value | Source |
|---|---|---|
| Expression Host | E. coli BL21(DE3) | |
| Induction Temperature | 18°C | |
| Yield (mg/L) | 8–12 | |
| Purity (%) | >90 |
Functional and Biochemical Insights
-
Enzymatic Activity: Recombinant SodA exhibits specific activity of ~3,500 U/mg at 25°C, with optimal pH 7.5–8.0 .
-
Thermal Stability: Retains 80% activity after 1 hour at 50°C, reflecting adaptation to aphid hemolymph conditions .
-
Metabolic Role: Protects Buchnera from host-derived ROS, ensuring symbiont survival and amino acid biosynthesis .
Applications in Research
-
Oxidative Stress Studies: Used to dissect ROS management in aphid-Buchnera symbiosis .
-
Biotechnological Tool: Serves as a model for engineering stress-tolerant microbial systems .
Limitations and Future Directions
Product Specs
Target Background
KEGG: buc:BU189
STRING: 107806.BU189
