Recombinant Burkholderia multivorans ATP synthase subunit b (atpF)

What is ATP synthase subunit b (atpF) in Burkholderia multivorans?

ATP synthase subunit b (atpF) is a protein component of the F0F1 ATP synthase complex in B. multivorans, which is crucial for energy metabolism and electron motive force generation. While not directly mentioned in the search results, the F0F1 ATP synthase complex is identified as an immunogenic protein in B. multivorans strains . The F0 portion, which includes subunit b, is embedded in the cytoplasmic membrane with a localization score of 7.88 as determined by subcellular prediction tools . Subunit b forms a critical stalk that connects the membrane-embedded F0 portion to the catalytic F1 portion, enabling the coupling of proton transport to ATP synthesis.

How does the atpF gene differ among Burkholderia species?

Comparative genomic analysis suggests variability in ATP synthase components across Burkholderia species. While the search results don't specifically address atpF sequence conservation, they indicate that Burkholderia species show both species-specific and shared immunogenic proteins . For instance, the F0F1 ATP synthase subunit alpha was identified as immunogenic in B. multivorans strains LMG13010 and C1962 . Researchers studying atpF should consider that gene sequence and expression patterns may differ between clinical isolates and environmental strains, potentially reflecting adaptations to different ecological niches.

What is the subcellular localization of atpF in B. multivorans?

The atpF protein, as part of the F0F1 ATP synthase complex, is predicted to be localized to the cytoplasmic membrane. According to the search results, the subcellular localization of F0F1 ATP synthase subunit alpha was determined using PSORTb V3, with a localization score of 9.97 for cytoplasmic proteins and 7.88 for cytoplasmic membrane proteins . The ATP synthase complex spans the membrane, with the F0 portion (including subunit b) embedded in the membrane and the F1 portion protruding into the cytoplasm. This transmembrane positioning is essential for its function in energy transduction.

How does atpF contribute to B. multivorans pathogenesis in CF patients?

ATP synthase components, including atpF, may contribute to pathogenesis through multiple mechanisms. The search results indicate that F0F1 ATP synthase subunit alpha is immunogenic in B. multivorans infections , suggesting that ATP synthase components are expressed during human infection and recognized by the host immune system. The immunogenic nature of ATP synthase components could indicate their accessibility to the immune system during infection or their release during bacterial lysis. Energy metabolism proteins like ATP synthase are crucial for bacterial survival in the host environment, particularly under the nutrient-limited conditions found in CF lungs. Further studies would be needed to determine whether atpF specifically contributes to virulence through mechanisms beyond basic energy metabolism.

What role might atpF play in B. multivorans biofilm formation?

While the search results don't directly address atpF's role in biofilm formation, they provide context about BDSF-based quorum sensing systems that regulate biofilm formation in Burkholderia species . ATP synthase function could be critical for providing energy for biofilm production and maintenance. Research has shown that fatty acid-based signaling molecules like BDSF control biofilm formation in Burkholderia . The energy requirements for exopolysaccharide production and biofilm matrix formation are considerable, making ATP synthase activity potentially important for these processes. Experimental approaches to study this connection could include creating atpF mutants and assessing their biofilm-forming capacity under various conditions.

How does atpF interact with other components of cell-to-cell signaling pathways?

The search results indicate that Burkholderia species employ sophisticated signaling systems, including AHL and BDSF-based quorum sensing . While not directly linked to atpF, these signaling systems regulate various cellular processes that require energy. The BDSF-based system influences intracellular c-di-GMP levels, which in turn affects gene expression . ATP synthase function could potentially be regulated by these signaling pathways to adjust energy production according to population density and environmental conditions. Research into the transcriptional regulation of ATP synthase genes in response to quorum sensing signals would be valuable for understanding these potential interactions.

What are the optimal expression systems for producing recombinant B. multivorans atpF?

Expression should be optimized by testing multiple conditions:

• Induction temperature (typically 16-30°C)

• IPTG concentration (0.1-1.0 mM)

• Induction duration (4-24 hours)

• Media composition (LB, TB, or minimal media)

The addition of membrane-mimicking environments during expression may improve yield and folding quality of this membrane-associated protein.

What purification strategies yield the highest purity of recombinant atpF?

Each preparation should be assessed for purity by SDS-PAGE and Western blotting using anti-His antibodies or custom atpF antibodies. For structural studies, additional purification steps may be necessary to achieve >95% purity.

How can researchers verify the proper folding and functionality of recombinant atpF?

Verifying proper folding and functionality of recombinant atpF requires multiple complementary approaches:

• Circular Dichroism (CD) Spectroscopy:

  • Analyze secondary structure content

  • Compare spectra with predicted models

  • Monitor thermal stability through temperature scans

• Limited Proteolysis:

  • Well-folded proteins show resistance to proteolytic degradation

  • Compare digestion patterns of recombinant protein with native protein

• Functional Assays:

  • Reconstitution into liposomes

  • Measure proton translocation using pH-sensitive fluorescent dyes

  • ATP synthase activity assays in reconstituted systems

• Binding Assays:

  • Verify interaction with other ATP synthase subunits using pull-down assays

  • Surface Plasmon Resonance (SPR) to measure binding kinetics

Since ATP synthase subunit b functions as part of a complex, its ability to form the correct oligomeric state and interact with partner subunits represents a critical quality control checkpoint.

How does the immunogenicity of atpF compare across different Burkholderia species?

The search results indicate significant variability in immunogenic proteins across Burkholderia species. The study found that only four proteins were immunogenic across all tested strains of B. multivorans and B. cenocepacia: GroEL, 38kDa porin, DNA-directed RNA polymerase, and elongation factor-Tu . F0F1 ATP synthase subunit alpha was only identified as immunogenic in B. multivorans strains, not in B. cenocepacia . This suggests species-specific immunogenicity patterns exist even for conserved proteins like ATP synthase components. The authors concluded that "a multi-component vaccine would be needed to protect CF patients from both B. multivorans and B. cenocepacia" . This species variability should be considered when evaluating atpF as a potential vaccine candidate.

What role might atpF play in a multi-component vaccine against Burkholderia infections?

While atpF itself isn't specifically mentioned in the search results as a vaccine candidate, the immunogenic nature of ATP synthase components suggests potential. The search results identify several consistently immunogenic proteins across Burkholderia species that could serve as vaccine candidates . ATP synthase components could potentially be included in a multi-component vaccine strategy. The authors note that "considerable differences in immunoreactive proteins were identified in the two B. cenocepacia strains" , highlighting the need for broadly cross-reactive antigens. For atpF to be considered as a vaccine component, researchers would need to:

• Confirm its conservation across clinical isolates

• Verify its expression during infection

• Determine its immunogenicity across patient populations

• Evaluate its ability to elicit protective rather than just reactive immunity

• Assess potential cross-reactivity with human proteins

What bioinformatic approaches can predict atpF structure and interactions?

Several bioinformatic approaches can provide insights into atpF structure and interactions:

The search results mention use of tools like PSORTb V3 for subcellular localization prediction , which assigns a score to indicate the confidence of localization predictions. Similar approaches combining multiple algorithms would provide robust predictions for atpF structure and interactions.

How can transcriptomic and proteomic data be integrated to understand atpF regulation?

Integration of transcriptomic and proteomic data provides a comprehensive view of atpF regulation:

• RNA-Seq Analysis:

  • Map reads to the B. multivorans genome

  • Quantify atpF transcript levels under different conditions

  • Identify co-expressed genes through cluster analysis

  • Determine transcription start sites using 5' RACE or dRNA-seq

• Proteomic Analysis:

  • Use methods similar to those described in the search results

  • Quantify protein abundance using label-free or labeled methods

  • Identify post-translational modifications

  • Confirm subcellular localization

• Data Integration:

  • Calculate correlation between transcript and protein levels

  • Identify potential translational regulation mechanisms

  • Apply pathway enrichment analysis to contextualize findings

  • Build regulatory network models incorporating quorum sensing pathways

The search results demonstrate the value of proteomic approaches for identifying proteins expressed during infection , which could be combined with transcriptomic data to understand the complex regulation of ATP synthase components under different conditions.

What are the most promising research directions for B. multivorans atpF studies?

Future research on B. multivorans atpF should focus on several key areas:

• Structural Biology:

  • High-resolution structures of atpF alone and in complex with other ATP synthase components

  • Comparison with homologs from other pathogens and hosts

• Host-Pathogen Interactions:

  • Role of ATP synthase in adaptation to the CF lung environment

  • Contribution to stress responses and antibiotic resistance

• Therapeutic Targeting:

  • Development of specific inhibitors of Burkholderia ATP synthase

  • Evaluation of atpF as part of multi-component vaccines

• Regulatory Networks:

  • Integration with quorum sensing pathways identified in the search results

  • Connections between energy metabolism and virulence regulation

These directions align with the broader research trends seen in the search results, which emphasize the importance of understanding both specific virulence factors and their regulatory networks in Burkholderia pathogenesis .

How might atpF research contribute to novel therapeutic approaches for CF patients?

Research on B. multivorans atpF could contribute to novel therapeutic approaches through several mechanisms:

• Vaccine Development:

  • The search results identify several immunogenic proteins that could serve as vaccine candidates

  • ATP synthase components might be part of a multi-epitope vaccine strategy

  • Understanding cross-species conservation would inform broad-spectrum vaccine development

• Drug Development:

  • ATP synthase-specific inhibitors could provide new antibiotic targets

  • Structure-based drug design targeting unique features of bacterial atpF

  • Combination therapies targeting energy metabolism and quorum sensing

• Diagnostic Applications:

  • Antibodies against immunogenic proteins could be used for rapid detection

  • Understanding the immunoproteome aids in developing serological tests

  • Monitoring antibody responses to specific proteins might predict disease progression

The search results emphasize the challenges of antibiotic resistance in Burkholderia infections , making these alternative therapeutic approaches particularly valuable for CF patients.