Recombinant Flavobacterium johnsoniae ATP synthase subunit alpha (atpA), partial

What is Recombinant Flavobacterium johnsoniae ATP synthase subunit alpha (atpA)?

Recombinant Flavobacterium johnsoniae ATP synthase subunit alpha (atpA) is a partial protein derived from the ATP synthase complex of F. johnsoniae. According to product specifications, it's produced in yeast expression systems with >85% purity (SDS-PAGE). The protein represents the alpha subunit of the F1 sector of ATP synthase, which plays a critical role in ATP synthesis. Commercial preparations (e.g., CSB-YP002344FDT) are derived from F. johnsoniae strain ATCC 17061/DSM 2064/UW101, also known as Cytophaga johnsonae .

ATP synthase subunit alpha has EC number 3.6.3.14 and functions as part of the F1 sector of the complete ATP synthase complex. In its native context, this protein would participate in the catalytic conversion of ADP to ATP using the energy derived from proton gradient across the membrane .

What are the optimal storage and handling conditions for recombinant F. johnsoniae atpA?

For successful experimental outcomes, researchers should adhere to these evidence-based storage and handling protocols:

Storage recommendations:

• Store stock at -20°C, or at -80°C for extended storage

• Avoid repeated freeze-thaw cycles

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

Reconstitution protocol:

• Centrifuge vial briefly before opening

• Reconstitute in deionized sterile water to 0.1-1.0 mg/mL

• Add glycerol to final concentration of 5-50% (50% is the default recommendation)

• Aliquot for long-term storage

Expected shelf life:

• Liquid form: approximately 6 months at -20°C/-80°C

• Lyophilized form: approximately 12 months at -20°C/-80°C

How does F. johnsoniae ATP synthase relate to the organism's unique properties?

F. johnsoniae is characterized by its gliding motility mechanism and ability to digest complex polysaccharides like chitin. While direct evidence linking ATP synthase to these properties isn't explicitly detailed in current research, several functional relationships can be inferred:

• Energy provision for gliding motility: F. johnsoniae employs a unique gliding mechanism that doesn't involve flagella or type IV pili but utilizes Gld proteins that comprise the "motor" and SprB, which functions as a cell surface adhesin . This specialized motility system requires ATP, making ATP synthase function critical.

• Support for polysaccharide digestion: F. johnsoniae can digest chitin, and research shows that nonmotile mutants fail to utilize this insoluble polysaccharide effectively . This suggests an interconnection between energy metabolism, motility, and polysaccharide utilization.

• Possible integration with specialized secretion systems: Comparative genomic analysis has revealed that some gliding motility genes (gld) may encode components of a novel protein secretion system in bacteroidetes , potentially requiring ATP generated by ATP synthase.

What experimental controls should be incorporated when conducting research with recombinant F. johnsoniae atpA?

When designing rigorous experiments with recombinant F. johnsoniae atpA, researchers should implement these methodological controls:

These controls are essential for producing reliable, reproducible data and identifying potential experimental artifacts when working with this recombinant protein.

What techniques are most effective for studying structural and functional aspects of F. johnsoniae atpA?

Modern research on ATP synthase components employs multiple complementary techniques:

• Structural analysis approaches:

  • X-ray crystallography for high-resolution structure determination

  • Cryo-electron microscopy for visualization in near-native states

  • Circular dichroism spectroscopy for secondary structure analysis

  • Hydrogen-deuterium exchange mass spectrometry for dynamic structural information

• Functional characterization methods:

  • ATP synthesis/hydrolysis assays using luminescence or colorimetric detection

  • Site-directed mutagenesis followed by kinetic analysis

  • Reconstitution experiments with other ATP synthase subunits

  • Proton pumping assays using pH-sensitive fluorophores

• Interaction studies:

  • Surface plasmon resonance for real-time binding kinetics

  • Pull-down assays to identify interaction partners

  • Isothermal titration calorimetry for thermodynamic characterization

  • Crosslinking coupled with mass spectrometry for interaction site mapping

When applying these techniques to recombinant F. johnsoniae atpA, researchers should consider that the commercial protein is partial , which may affect structural integrity or functional activity compared to the native form.

How can researchers optimize expression and purification of F. johnsoniae atpA for functional studies?

While the commercial protein is produced in yeast , researchers aiming to express and purify their own preparations should consider this optimization framework:

Expression system selection:

• Bacterial systems: E. coli BL21(DE3) or derivatives with rare codon supplementation

• Yeast systems: Pichia pastoris for potential better folding of this bacterial protein

• Cell-free systems: For rapid screening of expression constructs

Expression optimization strategies:

• Construct design:

  • Codon optimization for the selected expression host

  • Testing multiple fusion tags (His6, GST, MBP, SUMO)

  • Including TEV or PreScission protease sites for tag removal

  • Evaluating full-length versus functional domains

• Induction conditions:

  • Temperature gradient testing (15-37°C)

  • Inducer concentration optimization

  • Time-course analysis of expression

Purification workflow:

• Affinity chromatography (based on fusion tag)

• Ion-exchange chromatography

• Size-exclusion chromatography

• On-column refolding if necessary

Quality control checkpoints:

• SDS-PAGE and Western blotting at each purification stage

• Mass spectrometry for identity confirmation

• Dynamic light scattering for homogeneity assessment

• Activity assays to confirm functional integrity

How can F. johnsoniae atpA be used for taxonomic and phylogenetic studies?

The atpA gene has demonstrated significant utility for bacterial taxonomy and phylogenetics. For F. johnsoniae and related organisms, atpA offers these research applications:

• Molecular taxonomy: The atpA gene has been used successfully as a high-resolution marker for species identification within the Campylobacteraceae, enabling accurate identification of closely related species using a single primer pair . This approach could be adapted for taxonomic studies within Bacteroidetes.

• Phylogenetic analysis: Sequencing and comparative analysis of atpA can provide insights into evolutionary relationships among Bacteroidetes. The gene's essential function means it evolves under selective constraints, making it useful for resolving taxonomic relationships.

• Novel species identification: In studies of Campylobacter, atpA-based methods revealed "five putative novel Campylobacter taxa" , demonstrating the gene's value in identifying previously uncharacterized organisms. Similar approaches could reveal novel Flavobacterium species.

• Multi-locus sequence analysis: Combining atpA with other conserved markers can provide robust phylogenetic frameworks for studying the evolution of specialized traits within Bacteroidetes.

The sequence conservation pattern of atpA makes it particularly valuable for distinguishing closely related bacterial species that may be difficult to differentiate using 16S rRNA or other common markers.

What is the relationship between ATP synthase and the unique gliding motility mechanism of F. johnsoniae?

F. johnsoniae exhibits a novel gliding motility mechanism that differs fundamentally from flagellar or type IV pili-based motility seen in other bacteria. Current research suggests several connections between ATP synthase function and this specialized motility system:

• Energy requirements: The gliding machinery of F. johnsoniae comprises Gld proteins that form the "motor" and SprB, which functions as a cell surface adhesin . This motor-adhesin system requires energy in the form of ATP, directly linking ATP synthase activity to motility.

• Integrated regulatory networks: Given that nonmotile mutants of F. johnsoniae show deficiencies in chitin utilization , there appears to be regulatory integration between energy metabolism, motility, and polysaccharide degradation pathways.

• Specialized protein secretion connection: Comparative genomic analysis has revealed that some gld and spr genes (involved in gliding) are found in nongliding bacteroidetes and may encode components of a novel protein secretion system . This secretion machinery likely requires ATP, further connecting ATP synthase function to the broader cellular systems that support motility.

• Physiological evidence: The observation that mutations affecting F. johnsoniae motility also affect chitin utilization suggests that both processes may depend on shared energy resources, highlighting the central role of ATP synthase in supporting these specialized functions.

An integrated research approach combining genetics, biochemistry, and bioenergetics would be valuable for further elucidating these relationships.

How does F. johnsoniae ATP synthase structure compare with that of other bacterial species?

While detailed structural information specific to F. johnsoniae ATP synthase is not provided in the available research data, comparative analysis with other bacterial ATP synthases suggests several important considerations:

• Conserved core architecture: As a member of the bacterial F-type ATP synthases, F. johnsoniae ATP synthase likely maintains the fundamental architecture consisting of the membrane-embedded Fo sector (containing the c-ring) and the catalytic F1 sector containing the alpha and beta subunits arranged in a hexameric ring .

• Assembly process: Research on ATP synthase assembly indicates a conserved process involving "assembly of the c-ring followed by binding of F1, the stator arm, and finally of subunits a and A6L" . This assembly pathway may be conserved in F. johnsoniae.

• Modular construction: Studies suggest that bacterial ATP synthase is formed from three different modules: "the c-ring, F1 and the Atp6p/Atp8p complex" . This modular organization likely applies to F. johnsoniae ATP synthase as well.

• Taxonomic variations: As a member of the phylum Bacteroidetes, F. johnsoniae ATP synthase may contain unique structural adaptations that differentiate it from well-studied examples from Proteobacteria or Firmicutes. These adaptations could reflect the specific energy requirements of F. johnsoniae's lifestyle.

Structural determination of F. johnsoniae ATP synthase components would provide valuable insights into potential adaptations supporting its unique physiological properties.

What are the major challenges in studying the function of atpA in F. johnsoniae?

Researchers face several significant technical and conceptual challenges when investigating F. johnsoniae atpA:

• Multisubunit complexity: ATP synthase functions as a complex multisubunit enzyme. Studying the alpha subunit (atpA) in isolation presents challenges in understanding its native interactions and functional contributions within the complete complex.

• Genetic manipulation hurdles: While F. johnsoniae has been established as a model organism for studying bacteroidete gliding motility , genetic manipulation of this species presents greater technical challenges compared to traditional model bacteria like E. coli.

• Functional reconstitution: Reconstituting functional ATP synthase complexes in vitro requires multiple subunits and appropriate membrane environments, presenting significant biochemical challenges.

• Limitations of partial proteins: The commercially available recombinant protein is described as "partial" , potentially limiting its utility for functional studies if key domains are missing.

• Context-dependent function: F. johnsoniae's distinctive biological properties suggest potential adaptation of ATP synthase to specialized functions, which might not be readily apparent in standard biochemical assays developed for model organisms.

Addressing these challenges requires interdisciplinary approaches combining structural biology, biochemistry, genetics, and systems biology.

How can researchers explore the potential connection between ATP synthase and chitin utilization in F. johnsoniae?

Research has established a connection between motility and chitin utilization in F. johnsoniae, with nonmotile mutants showing deficiencies in chitin degradation . This suggests a complex relationship between energy metabolism, motility, and polysaccharide utilization. To explore these connections, researchers should consider:

• Metabolic flux analysis:

  • Measure ATP production rates during growth on different carbon sources

  • Compare energy consumption during active gliding versus stationary phases

  • Analyze ATP distribution between motility and hydrolytic enzyme production

• Genetic approaches:

  • Generate conditional atpA mutants and assess effects on motility and chitin utilization

  • Create fluorescently tagged ATP synthase to visualize localization relative to motility apparatus

  • Perform transcriptomic analysis to identify co-regulated genes across ATP synthesis, motility, and chitin degradation pathways

• Biochemical studies:

  • Investigate whether local ATP concentration affects gliding velocity

  • Examine if ATP synthase physically associates with components of the gliding machinery

  • Assess whether ATP levels modulate expression or secretion of chitinases

• Comparative analyses:

  • Compare ATP synthase structure and activity between F. johnsoniae and non-gliding relatives

  • Analyze energetic efficiency of closely related species with different chitin utilization capabilities

This research direction could provide fundamental insights into how bacteria integrate energy metabolism with specialized cellular functions.

What emergent applications might arise from advanced research on F. johnsoniae atpA?

Advanced research on F. johnsoniae atpA could yield several innovative applications:

• Novel taxonomic tools: The successful application of atpA sequencing for identification of Campylobacter species suggests similar potential for Bacteroidetes taxonomy. Developing atpA-based molecular identification methods could improve detection and classification of environmental Flavobacterium species.

• Biotechnological innovations: Understanding the structural and functional properties of F. johnsoniae ATP synthase could inform the development of engineered energy systems for biotechnological applications, particularly in microorganisms designed for polysaccharide degradation.

• Ecological monitoring tools: F. johnsoniae plays roles in environmental chitin degradation . AtpA-based detection methods could provide tools for monitoring the presence and activity of these organisms in natural ecosystems.

• Antimicrobial development: Structural differences between F. johnsoniae ATP synthase and homologs in other bacteria could potentially be exploited for the development of selective inhibitors, contributing to the antimicrobial discovery pipeline.

• Systems biology models: Detailed characterization of ATP synthase within the context of F. johnsoniae's specialized metabolic and motility systems could inform the development of improved computational models for bacterial energy metabolism and cellular function.

These applications would build upon the fundamental understanding gained through basic research on this important protein.

What is the current state of research on Flavobacterium johnsoniae ATP synthase?

Current research on F. johnsoniae ATP synthase remains relatively limited, with more attention being given to the organism's unique gliding motility mechanism and polysaccharide degradation capabilities. The available information suggests:

The limited available information indicates significant opportunities for future research to characterize F. johnsoniae ATP synthase and its role in supporting the organism's unique biological properties.

What comparative approaches can reveal evolutionary insights about F. johnsoniae atpA?

Comparative analysis of F. johnsoniae atpA can provide valuable evolutionary insights:

• Phylogenetic positioning: Analysis of atpA sequences across bacterial taxa can help resolve the evolutionary history of F. johnsoniae and related Bacteroidetes, similar to how atpA analysis has informed taxonomy of Campylobacteraceae .

• Functional adaptation signatures: Comparing atpA sequences between gliding and non-gliding Bacteroidetes could reveal selective pressures and adaptations related to the energy requirements of different lifestyles.

• Horizontal gene transfer assessment: Comparative genomic analysis can identify potential horizontal gene transfer events affecting ATP synthase components, providing insights into the acquisition of energy metabolism adaptations.

• Co-evolutionary patterns: Studying how atpA has co-evolved with other ATP synthase subunits or with proteins involved in specialized functions (like the gliding machinery) could illuminate the evolution of integrated biological systems.

• Structure-function relationships: Mapping sequence variations onto structural models can identify regions under different selective pressures, potentially revealing functional adaptations specific to F. johnsoniae's ecological niche.

These comparative approaches would contribute significantly to understanding how F. johnsoniae ATP synthase has evolved to support the organism's specialized biological functions.