Recombinant Desulfitobacterium hafniense Protein CrcB homolog 1 (crcB1)
Description
Introduction to Recombinant Desulfitobacterium hafniense Protein CrcB Homolog 1
The Recombinant Full Length Desulfitobacterium hafniense Protein CrcB Homolog 1 (crcB1) is a protein derived from the bacterium Desulfitobacterium hafniense, expressed recombinantly in E. coli systems for research purposes . This protein, also known by the synonyms DSY2097 and Putative fluoride ion transporter CrcB 1, has been assigned the UniProt ID Q24VQ6 . As a recombinant protein, it is typically produced with an N-terminal histidine tag to facilitate purification and experimental handling, making it valuable for various biochemical and structural studies.
The CrcB family of proteins appears across bacterial species and is characterized by their involvement in ion transport mechanisms, particularly fluoride ion transport. The crcB1 protein from Desulfitobacterium hafniense represents an important member of this protein family that has been made accessible through recombinant protein technology. The availability of this recombinant protein enables researchers to conduct detailed investigations into its structure-function relationships and potential applications in biotechnology.
Expression and Purification Methodologies
The production of recombinant Desulfitobacterium hafniense crcB1 protein involves heterologous expression in E. coli, which serves as an efficient host system for the production of bacterial proteins . The gene encoding the crcB1 protein is cloned into an appropriate expression vector that incorporates an N-terminal histidine tag, enabling subsequent purification through affinity chromatography methods.
For optimal handling of the purified protein, specific storage and reconstitution procedures are recommended. The recombinant crcB1 protein should be stored at -20°C to -80°C upon receipt, with aliquoting necessary for multiple use scenarios to avoid repeated freeze-thaw cycles that could compromise protein integrity . For reconstitution, it is advised to briefly centrifuge the protein vial prior to opening and to reconstitute the protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL . Addition of glycerol to a final concentration of 5-50% is recommended for long-term storage, with 50% being the default concentration .
These careful handling procedures ensure the stability and functional integrity of the recombinant protein for experimental applications, making it a reliable tool for biochemical and structural studies.
Biological Context: Desulfitobacterium hafniense
Understanding the biological context of the crcB1 protein requires examination of its source organism, Desulfitobacterium hafniense. This bacterium belongs to the Desulfitobacterium genus, which has gained recognition as one of the two most important groups of anaerobic dehalogenating bacteria . The genus was discovered relatively recently but has quickly become significant in environmental microbiology due to its unique metabolic capabilities.
Desulfitobacterium hafniense is an anaerobic, low-G+C, gram-positive, spore-forming bacterium that has attracted scientific interest primarily due to its ability to dechlorinate both aromatic and alkyl chlorinated compounds . These compounds include some of the most problematic environmental pollutants, such as chlorinated phenols and chlorinated ethenes that are widely used as solvents . There is also evidence suggesting that bacteria from this genus may dechlorinate polychlorinated biphenyls (PCBs) .
The strain most extensively studied, Desulfitobacterium hafniense strain DCB-2, has been demonstrated to grow by chlororespiration on chlorinated phenolic compounds . This metabolic capability highlights the ecological significance of this organism in environments contaminated with chlorinated organic pollutants. Recent studies have further identified Desulfitobacterium hafniense as a dechlorinating bacterium in enrichment cultures involved in the transformation of 2,4,5-T, a chlorinated compound .
Putative Function as a Fluoride Ion Transporter
The crcB1 protein from Desulfitobacterium hafniense is annotated as a "Putative fluoride ion transporter CrcB 1," suggesting its involvement in fluoride ion transport mechanisms across cell membranes . The CrcB family of proteins is found across various bacterial species and is characterized by its role in ion homeostasis, particularly in response to fluoride exposure.
Fluoride ion transporters serve critical functions in bacterial physiology, as fluoride can be toxic to cells at elevated concentrations by inhibiting essential enzymes. Transport proteins that mediate the efflux of fluoride ions from the cytoplasm represent an important mechanism of fluoride resistance in bacteria. While detailed functional characterization specific to the Desulfitobacterium hafniense crcB1 protein appears limited in the available literature, its classification within the CrcB family strongly suggests a role in fluoride homeostasis.
The membrane-associated nature of the crcB1 protein, as inferred from its amino acid sequence, aligns with this putative transport function. Further experimental work, such as fluoride uptake or efflux assays with the purified recombinant protein reconstituted in liposomes, would be valuable to definitively establish its functional role in fluoride ion transport.
Experimental Applications and Research Significance
The availability of recombinant Desulfitobacterium hafniense crcB1 protein opens numerous avenues for research investigations. As a putative membrane transporter, this protein represents an interesting target for structural studies that could elucidate the mechanisms of ion selectivity and transport across bacterial membranes.
Potential experimental applications for the recombinant crcB1 protein include:
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Structural determination through X-ray crystallography or cryo-electron microscopy
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Biochemical characterization of ion transport activity in reconstituted liposome systems
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Investigation of protein-ligand interactions to identify potential inhibitors
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Comparative studies with CrcB homologs from other bacterial species
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Exploration of the protein's role in the broader physiological context of Desulfitobacterium hafniense
The research significance of this protein extends beyond basic science to potential applications in biotechnology. Understanding the mechanisms of fluoride transport could inform strategies for enhancing bacterial resistance to fluoride in industrial applications or, conversely, for developing antimicrobial approaches targeting bacterial fluoride transporters.
Furthermore, research on the crcB1 protein contributes to our broader understanding of ion homeostasis in bacteria from extreme environments. Desulfitobacterium hafniense's ability to thrive in environments contaminated with halogenated compounds suggests specialized adaptations in its membrane transport systems, of which crcB1 may be a component.
Product Specs
Note: While we prioritize shipping the format currently in stock, we are happy to accommodate your specific format preferences. Please indicate your desired format in the order notes, and we will do our best to fulfill your request.
Note: All proteins are shipped with standard blue ice packs. If you require dry ice shipment, please communicate this in advance, as additional fees may apply.
Generally, the shelf life of liquid protein is 6 months at -20°C/-80°C. The shelf life of lyophilized protein is 12 months at -20°C/-80°C.
Target Background
KEGG: dsy:DSY2097
STRING: 138119.DSY2097
Q&A
What is the genomic context of CrcB homolog genes in Desulfitobacterium hafniense?
In D. hafniense, genomic organization reveals complex structures including insertion sequences and transposons that may influence gene expression and mobility. While specific information about CrcB homolog 1 is not directly available in the current literature, studies of D. hafniense strain TCE1 have demonstrated that important functional genes are often organized in clusters, similar to the pceABCT gene cluster which is flanked by a composite transposon structure (Tn-Dha1) . This transposon is composed of two identical insertion sequences (IS Dha1) belonging to the IS256 family . When investigating CrcB homolog 1, researchers should examine whether it exists within a similar mobile genetic element context, as this could provide insights into its evolutionary history and expression regulation.
What are the standard methods for recombinant expression of D. hafniense proteins?
For recombinant expression of D. hafniense proteins, researchers typically utilize E. coli-based expression systems with appropriate promoters and fusion tags to enhance solubility and facilitate purification. As demonstrated with D. hafniense DCB-2T reductive dehalogenase genes, heterologous expression in organisms like Shimwellia blattae has been successful for functional characterization . For recombinant CrcB homolog 1 expression, consider the following methodological approach:
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Design expression constructs with N- or C-terminal affinity tags (His6, GST, or MBP)
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Optimize codon usage for the selected expression host
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Test multiple expression conditions (temperature, induction time, media composition)
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Validate protein expression through Western blotting using tag-specific antibodies
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Optimize purification protocols using affinity chromatography followed by size-exclusion chromatography
This methodology has proven effective for other D. hafniense proteins and should be adaptable for CrcB homolog 1 expression.
How does D. hafniense adapt to different environmental conditions, and what role might CrcB homologs play?
D. hafniense demonstrates remarkable adaptability to various environmental conditions through genetic mechanisms including transposition and homologous recombination. The genetic heterogeneity around transposable elements like Tn-Dha1 suggests dynamic genome restructuring in response to environmental pressures . CrcB homologs, generally associated with fluoride ion resistance in bacteria, might play a role in this adaptability by providing protection against toxic halide ions.
When studying environmental adaptations, consider implementing:
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Growth studies under varying concentrations of fluoride and other halides
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Comparative transcriptomics of wild-type and crcB1 deletion mutants under stress conditions
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Fluoride ion sensitivity assays using recombinant strains with modified crcB1 expression
These approaches can help elucidate the specific role of CrcB homolog 1 in environmental adaptation mechanisms of D. hafniense.
What is the protein structure prediction for CrcB homolog 1 from D. hafniense?
While specific structural data for D. hafniense CrcB homolog 1 is not directly available in the provided information, general approaches to predict protein structure include:
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Primary sequence analysis using tools like BLAST and Clustal Omega to identify conserved domains
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Secondary structure prediction using algorithms such as PSIPRED or JPred
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Tertiary structure modeling using homology-based tools like SWISS-MODEL or AlphaFold2
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Validation of predicted structures using ProCheck or MolProbity
CrcB family proteins typically contain transmembrane domains forming ion channels. Researchers should verify predicted transmembrane regions using tools like TMHMM or Phobius when studying CrcB homolog 1.
How does genetic heterogeneity in D. hafniense populations affect the expression and function of proteins like CrcB homolog 1?
D. hafniense strain TCE1 populations display significant genetic heterogeneity, particularly around transposable elements. Studies have demonstrated that genetic rearrangements occur through multiple mechanisms, including transposition of insertion sequences and homologous recombination across identical copies of IS elements . This heterogeneity may impact the expression and function of various proteins, including potential CrcB homologs.
To investigate this question methodologically:
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Perform single-cell genomics on D. hafniense populations to quantify the prevalence of genetic variants
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Deploy targeted amplicon sequencing around the crcB1 locus in different growth conditions
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Use reporter gene fusions to monitor crcB1 expression in heterogeneous populations
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Correlate expression patterns with specific genetic variants using statistical approaches
This approach would reveal how genetic heterogeneity influences CrcB homolog 1 expression and potentially its function in different subpopulations.
What are the molecular mechanisms of CrcB homolog 1 function in halide ion resistance?
To elucidate the molecular mechanisms of CrcB homolog 1 function in D. hafniense, researchers should employ a multi-faceted approach combining genetic, biochemical, and biophysical techniques:
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Site-directed mutagenesis of conserved residues to identify functional domains
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Ion flux assays using fluorescent probes or radioisotopes to measure transport activity
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Electrophysiological studies using reconstituted proteoliposomes to characterize channel properties
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Protein-protein interaction studies to identify potential regulatory partners
CrcB proteins typically function as fluoride ion channels, and the transport mechanism likely involves conformational changes in transmembrane regions. Comparing the findings with known CrcB proteins from other organisms would provide context for understanding D. hafniense-specific adaptations.
How does the transcriptional regulation of crcB1 integrate with other stress response systems in D. hafniense?
D. hafniense possesses sophisticated transcriptional regulation systems, as evidenced by studies on reductive dehalogenase gene clusters. For example, in D. hafniense PCP-1, expression of cprA genes increases in a dose-dependent manner in the presence of chlorophenols, and multiple genes are induced in a sequential pattern in response to metabolic intermediates .
To investigate crcB1 transcriptional regulation:
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Perform RNA-seq under various stress conditions (halide exposure, pH stress, oxidative stress)
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Identify potential transcription factor binding sites upstream of crcB1 using bioinformatic approaches
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Validate interactions using electrophoretic mobility shift assays (EMSAs) or chromatin immunoprecipitation (ChIP)
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Construct reporter gene fusions to monitor expression patterns in real-time
This comprehensive approach would reveal how crcB1 regulation integrates with broader stress response networks in D. hafniense.
What technical challenges exist in structural biology studies of recombinant CrcB homolog 1?
Membrane proteins like CrcB homologs present significant challenges for structural biology studies. Researchers approaching structural characterization of recombinant CrcB homolog 1 should consider:
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Optimization of detergent screening for protein extraction and stability
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Nanodiscs or amphipol incorporation for maintaining native-like membrane environments
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Crystallization trials with various lipid cubic phase formulations
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Cryo-EM sample preparation optimizations for membrane proteins
Additionally, researchers might encounter specific challenges related to D. hafniense proteins, including potential post-translational modifications or cofactor requirements that are difficult to reproduce in recombinant systems.
How can gene editing approaches be optimized for studying crcB1 function in D. hafniense?
Genetic manipulation of D. hafniense requires specialized approaches due to its anaerobic lifestyle and potentially restrictive defense systems. Based on successful genetic studies in related organisms:
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Develop a CRISPR-Cas9 system optimized for anaerobic bacteria with appropriate delivery methods
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Design homologous recombination templates with selectable markers suitable for D. hafniense
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Implement inducible expression systems for complementation studies
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Establish protocols for confirming genetic modifications under anaerobic conditions
The table below summarizes potential genetic tools for D. hafniense manipulation:
| Genetic Tool | Application | Considerations for D. hafniense |
|---|---|---|
| CRISPR-Cas9 | Precise genome editing | Requires anaerobic transformation protocols |
| Homologous recombination | Gene knockout/replacement | Large flanking regions recommended (>1kb) |
| Transposon mutagenesis | Random mutagenesis | Leverages natural transposition mechanisms |
| Inducible promoters | Controlled gene expression | Test multiple inducers for efficiency |
| Fluorescent reporters | Gene expression monitoring | Oxygen-independent fluorophores required |
These methodologies would enable detailed functional characterization of crcB1 in its native genomic context.
What are the optimal conditions for measuring CrcB homolog 1 activity in vitro?
Designing robust assays for measuring CrcB homolog 1 activity requires careful consideration of protein function and physicochemical properties. For fluoride transport activity:
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Reconstitute purified protein in liposomes loaded with fluorescent indicators sensitive to fluoride ions
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Establish buffer conditions mimicking physiological environments (pH, salt concentration)
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Develop high-throughput assays using fluorescence-based detection in microplate format
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Include appropriate controls (liposomes without protein, inactive mutants)
Temperature, pH, and ion concentrations should be systematically varied to determine optimal activity conditions, which may provide insights into the ecological niche adaptation of D. hafniense.
How can heterologous expression systems be optimized for functional studies of CrcB homolog 1?
Based on studies with other D. hafniense proteins, heterologous expression systems can be optimized through:
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Testing multiple expression hosts beyond E. coli (e.g., Bacillus subtilis, Shimwellia blattae)
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Engineering synthetic operons that include potential accessory genes from D. hafniense
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Implementing anaerobic expression conditions to mimic the native environment
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Incorporating rare codon optimization and chaperon co-expression
As demonstrated with D. hafniense reductive dehalogenase rdhA3 (Dhaf_696), expression in Shimwellia blattae can preserve enzymatic activity . This suggests that similar approaches might be successful for functional expression of CrcB homolog 1.
What approaches can resolve contradictory data in CrcB homolog 1 research?
When faced with contradictory data in protein function studies, researchers should implement a systematic troubleshooting approach:
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Validate protein identity through mass spectrometry and N-terminal sequencing
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Verify protein folding using circular dichroism or limited proteolysis
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Employ multiple independent assay methods to cross-validate activity measurements
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Investigate strain-specific variations that might account for functional differences
Additionally, researchers should consider differences in experimental conditions (buffer composition, temperature, pH) that might explain contradictory results from different laboratories.
What are emerging technologies that could advance our understanding of CrcB homolog 1 function?
Several cutting-edge technologies hold promise for advancing research on D. hafniense CrcB homolog 1:
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Single-molecule tracking to visualize protein dynamics in live cells
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Cryo-electron tomography for visualizing membrane protein organization in native environments
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Metaproteomics for understanding CrcB homolog expression in environmental samples
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Deep mutational scanning to comprehensively map structure-function relationships
These approaches could provide unprecedented insights into the functional role of CrcB homolog 1 in D. hafniense physiology and its potential applications in bioremediation or synthetic biology.
How does understanding CrcB homolog 1 contribute to the broader field of environmental microbiology?
Research on D. hafniense CrcB homolog 1 contributes to our understanding of bacterial adaptations to environments containing halogenated compounds. The "physiological opportunism" of D. hafniense, as evidenced by its genomic plasticity and specialized metabolic capabilities, represents an important model for studying bacterial adaptation to anthropogenic contaminants .
Future studies integrating genomics, biochemistry, and environmental monitoring could reveal how proteins like CrcB homolog 1 contribute to microbial community functions in contaminated environments, potentially informing bioremediation strategies and environmental management practices.
