Recombinant Burkholderia pseudomallei UPF0060 membrane protein BURPS1710b_1597 (BURPS1710b_1597)

What is Burkholderia pseudomallei UPF0060 membrane protein BURPS1710b_1597?

The BURPS1710b_1597 protein is a membrane protein found in Burkholderia pseudomallei strain 1710b. It belongs to the UPF0060 family, which stands for "Unknown Protein Function," indicating that its precise function is not yet fully characterized. The protein has 110 amino acids with the sequence: mLSLAKIAALFVLTAVAEIVGCYLPWLVLKAGKPAWLLAPAALSLALFAWLLTLHPAAAARTYAAYGGVYIAVALAWLRIVDGVPLSRWDVAGAALALAGMSVIALQPRG. As an integral membrane protein, it is likely involved in bacterial membrane structure and potentially in pathogenicity .

Why is research on B. pseudomallei membrane proteins significant?

Research on B. pseudomallei membrane proteins is crucial because this bacterium is the causative agent of melioidosis, a disease with high morbidity and mortality in humans and animals, particularly in endemic regions. B. pseudomallei possesses two circular chromosomes containing numerous genes encoding virulence factors that promote infection in various hosts and survival within cells. Membrane proteins often play essential roles in bacterial virulence, pathogenesis, and host-pathogen interactions, making them important targets for vaccine development and therapeutic interventions .

What is the current understanding of UPF0060 family proteins?

The UPF0060 family proteins are identified through bioinformatics analysis but lack comprehensive functional characterization. While their specific functions remain unclear, structural analyses suggest they are integral membrane proteins with multiple transmembrane domains. Research indicates that some outer membrane proteins (OMPs) from B. pseudomallei demonstrate immunogenic properties and potential as vaccine candidates. Studies have shown that B. pseudomallei OmpA proteins specifically are immunogenic in mice and melioidosis patients, though the particular function of BURPS1710b_1597 within this context requires further investigation.

What is the recommended protocol for expression and purification of recombinant BURPS1710b_1597?

To express and purify recombinant BURPS1710b_1597, the protein is typically expressed in E. coli expression systems. The recommended protocol involves:

• Cloning the BURPS1710b_1597 gene into an appropriate expression vector with a His-tag or other affinity tag

• Transforming the construct into a competent E. coli strain optimized for membrane protein expression

• Inducing protein expression under controlled temperature conditions (typically 16-25°C)

• Harvesting cells and disrupting cell membranes using methods such as sonication or French press

• Solubilizing the membrane fraction using appropriate detergents

• Purifying using affinity chromatography with a Tris-based buffer containing 50% glycerol

• Storing purified protein at -20°C, or -80°C for extended storage

For optimal results, avoid repeated freeze-thaw cycles and store working aliquots at 4°C for up to one week .

How can novel protein solubilization approaches be applied to BURPS1710b_1597?

Recent advances in membrane protein solubilization techniques, such as the use of designed Water-soluble RFdiffused Amphipathic Proteins (WRAPs), could be applied to BURPS1710b_1597. This deep learning-based design approach creates proteins that surround the lipid-interacting hydrophobic surfaces of membrane proteins, rendering them stable and water-soluble without detergents. The methodology involves:

• Computational design of WRAP proteins specific to BURPS1710b_1597's structure

• Co-expression of the target protein with its WRAP partner

• Purification of the soluble complex

• Functional and structural characterization of the wrapped protein

This approach has been successful with both beta-barrel outer membrane and helical multi-pass transmembrane proteins, preserving their native fold, sequence, and function while enhancing stability. Given that B. pseudomallei membrane proteins present challenges for structural and functional characterization, WRAP technology could significantly advance research on BURPS1710b_1597 .

What methods are recommended for investigating the potential role of BURPS1710b_1597 in virulence?

To investigate the potential role of BURPS1710b_1597 in virulence, researchers should employ a multi-faceted approach:

• Gene Knockout Studies: Develop a BURPS1710b_1597 knockout strain using recombineering systems based on RecET-like operons, which have shown efficiency in Burkholderia species. Compare virulence phenotypes between wild-type and knockout strains in appropriate infection models .

• Protein Interaction Assays: Perform pull-down assays, bacterial two-hybrid screens, or co-immunoprecipitation to identify protein-protein interactions that may indicate involvement in virulence pathways.

• Host Response Analysis: Examine host immune responses to purified BURPS1710b_1597 protein, measuring cytokine production, neutrophil activation, and other immune parameters.

• Comparative Genomics: Analyze the conservation and variation of BURPS1710b_1597 across B. pseudomallei strains with different virulence profiles to identify potential correlations.

• Transcriptional Analysis: Use RNA-seq to compare expression patterns of BURPS1710b_1597 under different conditions that mimic the host environment versus standard laboratory conditions .

How can recombineering systems be optimized for studying BURPS1710b_1597 gene function?

Optimizing recombineering systems for studying BURPS1710b_1597 involves several critical considerations:

• Selection of Appropriate Recombinase: Based on comparative efficiency studies, RecETh TJI49 and RecETh1h2e YI23 show higher recombination efficiency compared to RecEThe BDU8 in Burkholderia species and would be recommended for BURPS1710b_1597 manipulation .

• Enhancement with Accessory Proteins: Include hypothetical proteins from RecETh1h2e YI23 and RecETh TJI49 operons that have demonstrated positive effects on recombination efficiency in Burkholderia .

• Exonuclease Inhibitor Incorporation: Combine RecET YI23 with exonuclease inhibitors such as Pluγ or Redγ to achieve higher recombination efficiency, comparable to Redγβα systems in E. coli .

• Promoter Selection: Optimize the strength and inducibility of promoters controlling recombinase expression to minimize toxicity while maximizing recombination efficiency.

• Temperature and Induction Conditions: Fine-tune temperature and inducer concentration based on preliminary optimization experiments specific to B. pseudomallei strain 1710b.

This optimized system enables precise genetic manipulation for functional studies of BURPS1710b_1597, including gene deletions, insertions, and point mutations .

What techniques are most effective for determining the structure of BURPS1710b_1597?

Given the challenges inherent in membrane protein structural determination, a combined approach is recommended:

• Cryo-Electron Microscopy (cryo-EM): This has become a method of choice for membrane proteins, potentially achieving resolutions of 4.0 Å or better, as demonstrated with other wrapped membrane proteins .

• X-ray Crystallography: If diffraction-quality crystals can be obtained, this method can provide high-resolution structural data. Specialized crystallization techniques for membrane proteins including lipidic cubic phase crystallization may be necessary.

• Nuclear Magnetic Resonance (NMR): For specific domains or segments of the protein, particularly those extending into aqueous phases.

• Computational Structure Prediction: Leveraging recent advances in AlphaFold2 and similar tools specialized for membrane proteins.

• Solubilization Strategies: Employing WRAP technology as described previously to facilitate structural studies without compromising native conformation .

A combination of these approaches, particularly integrating WRAP technology with cryo-EM, has proven successful with challenging membrane proteins and would likely be effective for BURPS1710b_1597 .

How should researchers approach the functional annotation of BURPS1710b_1597?

For functional annotation of this UPF0060 family protein with currently unknown function, researchers should implement a systematic approach:

• Comparative Sequence Analysis: Identify conserved domains and motifs through alignment with functionally characterized proteins, using tools like BLAST, HMMER, and the Pfam database.

• Structural Homology Modeling: Generate 3D models based on structural homologs to predict functional sites.

• Gene Neighborhood Analysis: Examine genomic context for clues about function, particularly genes frequently co-located or co-expressed with BURPS1710b_1597.

• Phenotypic Screening: Test knockout or overexpression strains under diverse conditions to identify phenotypic changes that suggest function.

• Transcriptomic and Proteomic Profiling: Compare expression patterns under different conditions to infer potential functional associations.

• Metabolite Analysis: For potential enzymatic functions, screen for substrate-product relationships using metabolomics approaches.

• Host-Pathogen Interaction Studies: Assess the protein's role during infection through infection models and cellular assays.

What methodologies are recommended for evaluating the immunogenic potential of BURPS1710b_1597?

To evaluate the immunogenic potential of BURPS1710b_1597, researchers should employ the following methodologies:

• Epitope Mapping:

  • In silico prediction of B-cell and T-cell epitopes

  • Peptide synthesis of predicted epitopes

  • ELISA or peptide array validation of epitope binding to antibodies

• Antibody Production and Characterization:

  • Immunization of animal models with purified BURPS1710b_1597

  • Collection and purification of polyclonal antibodies

  • Assessment of antibody specificity and affinity

  • Development of monoclonal antibodies against key epitopes

• T-Cell Response Analysis:

  • Isolation of peripheral blood mononuclear cells (PBMCs) from melioidosis patients

  • Stimulation with BURPS1710b_1597 antigens

  • Measurement of T-cell proliferation and cytokine production

  • Identification of immunodominant T-cell epitopes

• Cross-Protection Studies:

  • Immunization followed by challenge with live B. pseudomallei

  • Comparison of bacterial burden in immunized versus control groups

  • Survival analysis and histopathological examination

• Seroprevalence Studies in Endemic Regions:

  • Collection of serum samples from endemic areas

  • ELISA testing for anti-BURPS1710b_1597 antibodies

  • Correlation of antibody titers with protection or disease severity.

How can researchers design experiments to evaluate BURPS1710b_1597 as a vaccine candidate?

A comprehensive experimental design for evaluating BURPS1710b_1597 as a vaccine candidate should include:

• Antigen Preparation:

  Formulation	Preparation Method	Adjuvant	Dosage
  Recombinant protein	E. coli expression	Alum	10-50 μg
  DNA vaccine	Plasmid encoding BURPS1710b_1597	CpG	50-100 μg
  Viral vector	Adenovirus expressing BURPS1710b_1597	None	10^8-10^9 PFU
  Solubilized protein	WRAP technology	QS-21	25-75 μg

• Immunization Schedule:

  • Prime-boost strategies with varied intervals (2, 4, 8 weeks)

  • Route comparison (intramuscular, subcutaneous, intranasal)

  • Single vs. multiple boosting regimens

• Immune Response Evaluation:

  • Humoral immunity: antibody titers, isotype distribution, neutralization capacity

  • Cellular immunity: T-cell proliferation, cytokine profiling, CD4+/CD8+ responses

  • Mucosal immunity: secretory IgA levels, mucosal lymphocyte activation

• Challenge Studies:

  • Dose-ranging studies to determine optimal challenge dose

  • Multiple challenge routes (aerosol, intranasal, intraperitoneal)

  • Time-course analysis of bacterial clearance

  • Histopathological analysis of affected tissues

• Correlates of Protection Analysis:

  • Statistical correlation between immune parameters and protection

  • Passive transfer studies to determine protective antibody thresholds

  • Adoptive transfer of T-cells to assess cellular immunity contribution.

How might BURPS1710b_1597 interact with host cell machinery during infection?

Based on current understanding of bacterial membrane proteins and pathogenesis mechanisms, BURPS1710b_1597 might interact with host cell machinery through several potential mechanisms:

• Membrane Integrity Modulation: The protein's sequence suggests multiple transmembrane domains that could participate in forming pores or channels, potentially disrupting host cell membrane integrity or facilitating molecular transport.

• Immune Recognition Evasion: As an outer membrane protein, BURPS1710b_1597 may have evolved structures that mimic host proteins or mask pathogen-associated molecular patterns (PAMPs) from pattern recognition receptors.

• Adhesion and Invasion: The protein might function as an adhesin, binding to specific host cell receptors to facilitate bacterial attachment and subsequent invasion.

• Host Signaling Pathway Interference: BURPS1710b_1597 could potentially interact with host signaling molecules, disrupting normal cellular responses to infection.

• Nutrient Acquisition: The protein might be involved in acquiring essential nutrients from the host environment, particularly metal ions or complex organic molecules.

Experimental approaches to investigate these interactions should include protein-protein interaction studies, host cell infection models with wild-type versus knockout strains, and comparative proteomics of host cell membrane fractions following infection.

What are the challenges and solutions for studying post-translational modifications of BURPS1710b_1597?

Studying post-translational modifications (PTMs) of bacterial membrane proteins like BURPS1710b_1597 presents several unique challenges:

To successfully characterize PTMs:

• Employ mass spectrometry-based approaches optimized for membrane proteins:

  • Specialized solubilization using MS-compatible detergents

  • Multiple protease digestion strategies to maximize coverage

  • Electron transfer dissociation (ETD) for labile modifications

• Complement with site-directed mutagenesis:

  • Mutate potential modification sites

  • Assess functional consequences of preventing specific PTMs

• Develop temporal profiling methods:

  • Sample at multiple timepoints during infection process

  • Correlate PTM changes with infection stages

• Apply native mass spectrometry:

  • Analyze intact protein complexes with modifications

  • Preserve non-covalent interactions during analysis .

How might systems biology approaches advance understanding of BURPS1710b_1597 in B. pseudomallei pathogenesis?

Systems biology approaches offer powerful frameworks for contextualizing BURPS1710b_1597 within the broader pathogenesis mechanisms of B. pseudomallei:

• Multi-omics Integration:

  • Combine transcriptomics, proteomics, and metabolomics data

  • Create comprehensive network models of protein-protein interactions

  • Identify regulatory networks controlling BURPS1710b_1597 expression

  • Map metabolic pathways potentially influenced by the protein

• Host-Pathogen Interactome Mapping:

  • Construct interaction networks between B. pseudomallei and host proteins

  • Position BURPS1710b_1597 within these networks

  • Identify critical nodes and potential therapeutic targets

  • Model dynamics of interactions during infection progression

• Computational Modeling of Infection:

  • Develop agent-based models incorporating BURPS1710b_1597 function

  • Simulate infection scenarios with varying expression levels

  • Predict outcomes of therapeutic interventions targeting the protein

  • Model evolutionary adaptations under selective pressure

• Comparative Systems Analysis:

  • Cross-species comparison of UPF0060 family proteins

  • Correlate functional differences with pathogenicity

  • Identify conserved vs. species-specific interaction patterns

  • Map evolutionary trajectories of membrane protein functions .

What novel recombinant protein applications could be developed using BURPS1710b_1597?

The unique properties of BURPS1710b_1597 present opportunities for several innovative applications:

• Diagnostic Tools:

  • Development of recombinant antibody-based diagnostic kits

  • Creation of aptamer-based biosensors for rapid B. pseudomallei detection

  • Lateral flow assays for field diagnosis in endemic regions

  • Multiplexed detection systems incorporating multiple bacterial antigens

• Vaccine Technology:

  • Multi-epitope vaccines incorporating immunogenic regions

  • Nanoparticle display platforms for enhanced immunogenicity

  • Prime-boost strategies combining DNA and protein delivery

  • Mucosal delivery systems targeting respiratory immunity

• Therapeutic Protein Engineering:

  • Engineered decoy proteins to disrupt bacterial virulence

  • Immunomodulatory constructs to direct specific immune responses

  • Targeted delivery of antimicrobial compounds

  • Anti-adhesin therapies preventing bacterial attachment

• Research Tools:

  • Fluorescently tagged versions for live-cell imaging

  • Protein scaffolds for studying membrane protein interactions

  • Affinity reagents for isolating host-cell binding partners

  • Structural templates for designing inhibitors of related proteins .