Recombinant Buchnera aphidicola subsp. Acyrthosiphon pisum Single-stranded DNA-binding protein (ssb)
Description
Definition and Biological Context
Recombinant SSB proteins are laboratory-engineered versions of natural ssb proteins, often expressed in heterologous systems (e.g., E. coli) for structural or functional studies. In Buchnera aphidicola, ssb proteins are critical for DNA replication, repair, and homologous recombination, particularly under the symbiont’s obligate intracellular lifestyle. These proteins bind single-stranded DNA (ssDNA) to stabilize it, prevent degradation, and facilitate enzymatic processes like DNA polymerase activity .
The Acyrthosiphon pisum subspecies of Buchnera aphidicola (strain APS) is renowned for its extreme genome reduction, with genes retained primarily for essential metabolic functions, including amino acid biosynthesis . While ssb genes are not explicitly mentioned in Buchnera genome studies, their presence is inferred from conserved roles in bacterial genome stability .
General SSB Protein Features
Hypothetical Buchnera SSB Properties
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Function: Likely stabilizes ssDNA during replication and repair, compensating for Buchnera’s reduced genome repair machinery .
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Thermal Adaptation: While Buchnera resides in aphids at ambient temperatures, its ancestral Enterobacteriaceae lineage suggests moderate thermal stability.
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RNA Interactions: Some ssb proteins bind RNA , potentially influencing viral RNA metabolism in aphids .
Case Study: Recombinant Buchnera UPF0114 Protein
A recombinant UPF0114 protein (UniProt: Q89B48) from Buchnera aphidicola subsp. Baizongia pistaciae was expressed in E. coli with an N-terminal His tag . Key specifications:
| Parameter | Value |
|---|---|
| Length | Full-length (1–165 amino acids) |
| Purity | >90% (SDS-PAGE) |
| Form | Lyophilized powder |
| Storage | -20°C/-80°C; avoid freeze-thaw cycles |
| Expression Host | E. coli |
This example highlights methodologies applicable to Acyrthosiphon pisum ssb production, including His-tagging for purification and E. coli-based expression systems.
SSB in Genome Stability
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Mutation Avoidance: SSB deletion in Sulfolobus acidocaldarius increased mutation rates 29-fold, underscoring its role in error-free replication .
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Homologous Recombination: ComM helicase in Vibrio cholerae enables branch migration during DNA integration, analogous to potential Buchnera ssb functions .
Aphid-Symbiont Interactions
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Amino Acid Metabolism: Buchnera provides essential amino acids (e.g., tryptophan, leucine) to aphids, relying on ssb-mediated genome stability to maintain biosynthetic pathways .
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Transport Mechanisms: Symbiosomal membrane transporters (e.g., ApNEAAT1) mediate amino acid exchange, which may indirectly depend on ssb-stabilized DNA .
Gaps and Future Directions
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Direct Studies: No studies explicitly characterize Acyrthosiphon pisum Buchnera ssb. Prioritizing its isolation and functional analysis is critical.
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Functional Genomics: CRISPR-based gene interference (e.g., antisense PNAs) could test groEL or ssb roles in Buchnera .
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Thermal Tolerance: Comparative studies of Buchnera ssb and thermophilic ssb (e.g., Thermococcus) could reveal evolutionary adaptations.
Product Specs
Target Background
KEGG: buc:BU545
STRING: 107806.BU545
