Recombinant Pseudomonas aeruginosa UPF0114 protein PSPA7_5214 (PSPA7_5214)

How is recombinant PSPA7_5214 protein typically expressed and purified?

Recombinant PSPA7_5214 protein is most commonly expressed using E. coli expression systems . The production process involves:

• Cloning the full-length gene sequence (1-162 aa) into a suitable expression vector

• Transformation into E. coli host cells optimized for recombinant protein expression

• Induction of protein expression under controlled conditions

• Cell lysis and extraction of the recombinant protein

• Purification via affinity chromatography, typically using the His-tag for immobilized metal affinity chromatography (IMAC)

The purified protein typically achieves greater than 90% purity as determined by SDS-PAGE analysis . While E. coli is the predominant expression system, alternative expression platforms including yeast, baculovirus-infected insect cells, or mammalian cell systems may be employed for specific experimental requirements .

What are the optimal storage conditions for preserving PSPA7_5214 protein activity?

To maintain optimal activity and stability of recombinant PSPA7_5214 protein, the following storage conditions are recommended:

• Store lyophilized protein at -20°C/-80°C upon receipt

• For reconstituted protein, prepare aliquots to avoid repeated freeze-thaw cycles

• Working aliquots can be stored at 4°C for up to one week

• For long-term storage, add glycerol (final concentration 6-50%) and store at -20°C/-80°C

• Reconstitute lyophilized protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL

The protein is typically stored in Tris/PBS-based buffer with 6% trehalose at pH 8.0 . Repeated freeze-thaw cycles significantly reduce protein activity and should be avoided through careful aliquoting of the reconstituted protein .

What functional roles has PSPA7_5214 been implicated in within Pseudomonas aeruginosa biology?

While the precise function of PSPA7_5214 has not been fully characterized, its classification as a UPF0114 family protein suggests potential roles in membrane-associated processes. The protein's amino acid sequence indicates multiple transmembrane domains, suggesting it may function in:

• Membrane integrity maintenance

• Small molecule transport across the cell membrane

• Signaling pathways involving membrane components

Research on related Pseudomonas aeruginosa membrane proteins indicates potential involvement in antibiotic resistance mechanisms and virulence pathways . For instance, other membrane-associated proteins in P. aeruginosa have been linked to ABC transport systems that mediate uptake of peptidyl nucleoside antibiotics . While direct evidence for PSPA7_5214's participation in these processes is limited in the current literature, the protein's sequence and predicted structure suggest similar functional possibilities.

How can recombinant PSPA7_5214 be utilized in vaccine development research against Pseudomonas aeruginosa?

Recombinant PSPA7_5214 has potential applications in vaccine development against Pseudomonas aeruginosa, a multidrug-resistant pathogen associated with serious hospital-acquired infections . Experimental approaches include:

• Antigen identification and characterization: PSPA7_5214 can be evaluated as a potential vaccine antigen through immunogenicity studies, determining if it elicits protective antibody responses .

• Bionanoparticle development: Research on P. aeruginosa outer-membrane-vesicle (OMV) vaccines demonstrates that recombinant proteins can be incorporated into OMVs to generate enhanced immune responses. Similar approaches could be applied to PSPA7_5214 .

• Multi-epitope vaccine design: PSPA7_5214 epitopes could be combined with other P. aeruginosa antigens to create multi-epitope vaccines targeting multiple virulence factors simultaneously.

In recent studies, recombinant P. aeruginosa proteins incorporated into OMVs demonstrated up to 70% protection in animal challenge models . This suggests that properly formulated recombinant proteins can induce protective immunity against P. aeruginosa infection.

What experimental methods are most effective for studying PSPA7_5214 protein-protein interactions?

Investigating protein-protein interactions of PSPA7_5214 requires specialized approaches due to its membrane-associated nature. Recommended methodological approaches include:

• Co-immunoprecipitation (Co-IP): Utilizing anti-His antibodies to precipitate PSPA7_5214 and identify binding partners through mass spectrometry. This approach has successfully identified protein-protein interactions in other P. aeruginosa membrane proteins .

• Yeast two-hybrid system with membrane adaptations: Modified membrane yeast two-hybrid systems can overcome limitations of traditional Y2H for membrane proteins.

• Biolayer interferometry (BLI) or surface plasmon resonance (SPR): These techniques allow real-time, label-free detection of protein-protein interactions with purified recombinant PSPA7_5214.

• Protein crosslinking coupled with mass spectrometry: This approach can capture transient interactions in native membrane environments.

• Bacterial two-hybrid systems: These have been successfully employed to study interactions between bacterial membrane proteins and could be adapted for PSPA7_5214.

When designing these experiments, researchers should account for the hydrophobic nature of PSPA7_5214 and incorporate appropriate detergents or membrane mimetics to maintain the protein in its native conformation .

What analytical techniques are recommended for confirming the structural integrity of recombinant PSPA7_5214?

To ensure the structural integrity and proper folding of recombinant PSPA7_5214, researchers should employ multiple complementary analytical techniques:

• SDS-PAGE and Western blotting: Basic validation of protein size, purity (>90% recommended), and identity using anti-His antibodies .

• Circular dichroism (CD) spectroscopy: Analysis of secondary structure elements to confirm proper protein folding, particularly important for membrane proteins.

• Size exclusion chromatography (SEC): Assessment of protein homogeneity and oligomeric state.

• Mass spectrometry: Confirmation of exact molecular weight and potential post-translational modifications.

• Functional assays: Development of activity assays based on predicted function to confirm biological activity.

For membrane proteins like PSPA7_5214, additional techniques such as differential scanning calorimetry (DSC) or differential scanning fluorimetry (DSF) can provide insights into protein stability and the effects of buffer conditions or ligands on protein folding .

What are the most common challenges in expressing and purifying functional PSPA7_5214, and how can they be addressed?

Expressing and purifying membrane-associated proteins like PSPA7_5214 presents several challenges that require specific troubleshooting approaches:

For PSPA7_5214 specifically, expression in E. coli has been successful when using an N-terminal His-tag and purification under denaturing conditions, followed by controlled refolding . Including 6% trehalose in the storage buffer enhances stability .

How can researchers design experiments to investigate the potential role of PSPA7_5214 in antibiotic resistance mechanisms?

To investigate PSPA7_5214's potential role in antibiotic resistance, researchers could implement the following experimental design:

• Gene knockout/knockdown studies:

  • Generate PSPA7_5214 deletion mutants in P. aeruginosa

  • Assess changes in minimum inhibitory concentrations (MICs) for various antibiotic classes

  • Perform complementation studies to confirm phenotype specificity

• Protein overexpression analysis:

  • Create strains overexpressing PSPA7_5214

  • Determine if increased expression correlates with altered antibiotic susceptibility

• Transport assays:

  • Develop fluorescently labeled antibiotic uptake assays

  • Compare uptake rates between wild-type and PSPA7_5214 mutant strains

  • Investigate if PSPA7_5214 functions similarly to known antibiotic transporters like the NppA1A2BCD system

• Protein localization studies:

  • Generate fluorescently tagged PSPA7_5214 to determine subcellular localization

  • Assess co-localization with known resistance determinants

• Clinical isolate correlation:

  • Analyze PSPA7_5214 expression levels in resistant vs. susceptible clinical isolates

  • Sequence the gene from diverse isolates to identify potential resistance-associated polymorphisms

This multi-faceted approach would provide comprehensive insights into whether PSPA7_5214 contributes to antibiotic resistance mechanisms in P. aeruginosa .

What methods can be used to evaluate the immunogenicity of PSPA7_5214 for vaccine development?

Evaluating the immunogenicity of PSPA7_5214 for vaccine development requires a systematic approach spanning in silico, in vitro, and in vivo methodologies:

• In silico epitope prediction:

  • Use computational tools to identify B-cell and T-cell epitopes within PSPA7_5214

  • Assess epitope conservation across diverse P. aeruginosa strains

  • Predict MHC-binding affinity of potential epitopes

• In vitro antibody generation and characterization:

  • Immunize animals with purified recombinant PSPA7_5214

  • Generate monoclonal antibodies against specific epitopes

  • Evaluate antibody binding affinity and specificity using ELISA, SPR, or BLI

• Functional antibody assays:

  • Opsonophagocytosis assays to assess antibody-mediated bacterial clearance

  • Complement-dependent cytotoxicity assays

  • Neutralization assays if PSPA7_5214 has a known virulence function

• Cellular immunity assessment:

  • T-cell proliferation assays in response to PSPA7_5214 stimulation

  • Cytokine profiling to characterize Th1/Th2/Th17 responses

  • Adoptive transfer experiments to evaluate protective capacity

• In vivo protection studies:

  • Challenge immunized animals with virulent P. aeruginosa

  • Assess survival rates, bacterial burden, and inflammatory markers

  • Compare protection with established vaccine candidates

This comprehensive approach would determine whether PSPA7_5214 is a viable vaccine antigen against P. aeruginosa infections, similar to evaluations performed for other recombinant P. aeruginosa proteins .

What synergies exist between PSPA7_5214 research and studies on Pseudomonas aeruginosa outer membrane vesicles (OMVs)?

Research on PSPA7_5214 complements studies on P. aeruginosa outer membrane vesicles (OMVs) in several important ways:

• Protein incorporation into OMVs: As a membrane-associated protein, PSPA7_5214 may naturally incorporate into OMVs produced by P. aeruginosa. Studies have demonstrated that recombinant proteins can be engineered to increase their presence in OMVs, enhancing their immunogenicity .

• Vaccine development platforms: P. aeruginosa OMVs are being explored as vaccine platforms, with recombinant strain PA-m14 designed to eliminate virulence factors while enhancing immunogenic properties. PSPA7_5214 could potentially be incorporated into such systems as an additional antigen .

• Functional studies: OMVs represent a natural membrane environment that may maintain PSPA7_5214 in its native conformation, facilitating functional studies that are challenging with purified recombinant protein.

• Delivery systems: OMVs can function as natural delivery vehicles for membrane proteins like PSPA7_5214, potentially enhancing immune responses compared to soluble protein formulations.

Research has shown that immunization with engineered P. aeruginosa OMVs carrying specific antigens provided up to 70% protection against intranasal challenge in animal models . This suggests that incorporating PSPA7_5214 into OMV-based vaccine platforms could be a promising approach if the protein proves immunogenic.

How can researchers integrate PSPA7_5214 studies within the broader context of Pseudomonas aeruginosa pathogenesis research?

Integration of PSPA7_5214 research into the broader understanding of P. aeruginosa pathogenesis requires a multidisciplinary approach:

• Systems biology integration:

  • Incorporate PSPA7_5214 into protein-protein interaction networks

  • Analyze transcriptomic data to identify conditions that modulate PSPA7_5214 expression

  • Create metabolic models that include PSPA7_5214's potential role in nutrient acquisition

• Virulence mechanism studies:

  • Evaluate PSPA7_5214 expression during infection using in vivo transcriptomics

  • Assess contribution to biofilm formation, a key virulence determinant

  • Investigate potential roles in host-pathogen interactions

• Comparative genomics approaches:

  • Analyze PSPA7_5214 conservation across clinical isolates from various infection sites

  • Identify potential correlations between sequence variations and virulence phenotypes

  • Compare with homologs in other pathogens to derive functional insights

• Multi-omics integration:

  • Combine proteomics, transcriptomics, and metabolomics data to place PSPA7_5214 in functional pathways

  • Use this integrated approach to generate testable hypotheses about PSPA7_5214 function

• Collaborative research frameworks:

  • Establish research consortia focusing on membrane protein characterization

  • Share reagents, mutant strains, and experimental protocols to accelerate discoveries

By placing PSPA7_5214 research within this broader context, researchers can contribute to the comprehensive understanding of P. aeruginosa pathogenesis while addressing specific questions about this understudied protein .