Recombinant Bacillus cereus Probable disulfide formation protein C 1 (bdbC1)
Description
Molecular Identity and Basic Properties
Bacillus cereus Probable disulfide formation protein C 1, commonly referred to as bdbC1, is a membrane-associated oxidoreductase involved in disulfide bond formation in the bacterial cell envelope . This protein is encoded by the bdbC1 gene (locus tag BCE_0823) in B. cereus and belongs to the thioredoxin-like superfamily of proteins . The full-length protein consists of 139 amino acid residues with a molecular structure that includes critical catalytic cysteine residues essential for its oxidoreductase function .
Comparative Analysis
Table 1: Comparison of bdbC1 with Other Bacterial Disulfide Formation Proteins
Role in Disulfide Bond Formation
In Bacillus cereus, bdbC1 functions as a key component in the disulfide bond formation pathway, which is essential for the proper folding and stability of exported proteins, including virulence factors . Similar to the DsbA/DsbB system in Gram-negative bacteria, bdbC1 likely catalyzes the oxidation of free thiol groups in substrate proteins to form disulfide bridges .
The mechanism likely involves a nucleophilic attack by an active cysteine residue in the CXXC motif of bdbC1 on substrate protein thiols, resulting in the formation of a mixed disulfide intermediate that resolves to form a disulfide bond in the substrate while reducing bdbC1 . The reduced bdbC1 is subsequently reoxidized by other components of the cellular redox machinery, enabling catalytic cycling of the protein .
Significance in Bacterial Pathogenesis
Disulfide bond formation proteins play crucial roles in bacterial virulence by ensuring the proper folding of secreted toxins and enzymes . In B. cereus, a foodborne pathogen responsible for gastrointestinal and non-gastrointestinal infections, the structural integrity of enterotoxins and other virulence factors depends on correct disulfide bond formation . The bdbC1 protein likely contributes to the assembly and stability of these virulence determinants, indirectly influencing the pathogenic potential of the bacterium .
Additionally, disulfide formation proteins have been implicated in bacterial adaptation to environmental stresses and in the formation of biofilms, which enhance bacterial persistence in diverse ecological niches . The proper functioning of bdbC1 may therefore contribute to the ecological success and pathogenicity of B. cereus .
Expression Systems and Production Methods
Recombinant bdbC1 has been successfully expressed in various heterologous systems, with Escherichia coli being the most commonly utilized host . Expression typically involves cloning the bdbC1 gene into suitable expression vectors that allow for the addition of affinity tags for subsequent purification.
Table 2: Production Parameters for Recombinant bdbC1
Functional Characterization
The functionality of recombinant bdbC1 can be assessed through various biochemical assays that measure its oxidoreductase activity. These typically involve monitoring the formation or isomerization of disulfide bonds in model substrate proteins . The protein may exist in different oligomeric states depending on the redox environment, with the potential formation of intramolecular and intermolecular disulfide bonds affecting its functional properties .
Structure-Function Studies
Recombinant bdbC1 serves as a valuable tool for investigating the mechanisms of disulfide bond formation in Gram-positive bacteria . Structural studies, including X-ray crystallography and nuclear magnetic resonance spectroscopy, can provide insights into the protein's active site architecture and substrate recognition features .
Drug Discovery and Development
As bacterial disulfide bond formation pathways are essential for virulence in many pathogens, proteins like bdbC1 represent potential targets for antimicrobial development . Inhibitors of bdbC1 could potentially disrupt the correct assembly of B. cereus virulence factors, thereby attenuating its pathogenicity . The availability of recombinant bdbC1 facilitates high-throughput screening for such inhibitors and structure-based drug design efforts.
Biotechnological Applications
Beyond its relevance to pathogenesis, recombinant bdbC1 holds promise for biotechnological applications . The protein's ability to catalyze disulfide bond formation could be harnessed for the industrial production of disulfide-rich proteins, including therapeutic antibodies and peptides . Additionally, engineered variants of bdbC1 with enhanced catalytic properties or altered substrate specificities could serve as valuable tools in protein engineering endeavors .
Comparative Genomics and Evolution
Recent genomic analyses have revealed that bacteria often possess multiple disulfide bond formation proteins with potentially overlapping and specialized functions . In B. cereus, the presence of bdbC1 and related proteins like bdbC2 suggests a complex and possibly redundant system for ensuring proper protein folding . Comparative studies of these paralogs could provide insights into their evolutionary history and functional diversification.
Integration with Other Cellular Processes
Emerging evidence suggests that bacterial disulfide bond formation systems are integrated with other cellular processes, including stress responses and redox homeostasis . Future research could explore the potential connections between bdbC1 function and B. cereus adaptation to environmental stresses, biofilm formation, and host-pathogen interactions .
Technological Innovations
Advances in protein engineering and synthetic biology offer exciting opportunities for exploiting bdbC1 in novel applications . Designer variants of the protein with enhanced stability, altered substrate specificity, or novel catalytic properties could find applications in the production of complex biopharmaceuticals or the development of biosensors for detecting specific molecular interactions .
Product Specs
Note: We will prioritize shipping the format currently in stock. However, if you have specific format requirements, please indicate them in your order. We will prepare the product according to your request.
Note: All our proteins are shipped with standard blue ice packs. If you require dry ice shipping, please notify us in advance as additional fees will apply.
Generally, the shelf life of the liquid form is 6 months at -20°C/-80°C. The shelf life of the lyophilized form is 12 months at -20°C/-80°C.
Target Background
KEGG: bca:BCE_0823
Q&A
What is the biological function of Bacillus cereus bdbC1?
Bacillus cereus bdbC1 is a probable disulfide formation protein that likely participates in the formation of disulfide bonds within proteins in the bacterial cytoplasm. These disulfide bonds are essential for proper protein folding and stability, particularly during conditions of oxidative stress. Similar to other disulfide bond formation proteins, bdbC1 likely catalyzes the oxidation of thiol groups in cysteine residues to form disulfide bridges, which can be crucial for the structural integrity and function of various proteins including virulence factors . The formation of these disulfide bonds is often regulated in response to changes in the cellular redox environment, suggesting that bdbC1 may play a role in B. cereus adaptive responses to environmental stresses.
How does bdbC1 differ from other disulfide formation proteins in the Bacillus genus?
While the search results don't provide specific details about bdbC1 compared to other disulfide formation proteins in Bacillus species, it's important to note that B. cereus belongs to a diverse group that includes several closely related species such as B. anthracis, B. thuringiensis, and others . The B. cereus group shows considerable genetic diversity despite being closely related. This suggests that while bdbC1 likely shares core functional domains with disulfide formation proteins from related Bacillus species, it may have unique characteristics that reflect the specific ecological niche and pathogenic potential of B. cereus. Evolutionary analysis using techniques similar to the multilocus sequence typing described for B. cereus isolates could help place bdbC1 in the context of related proteins across the genus .
What is the relationship between bdbC1 and B. cereus virulence?
Bacillus cereus is known for causing food poisoning and opportunistic infections, with its pathogenicity dependent on various virulence factors including enterotoxins . While the specific role of bdbC1 in virulence isn't directly addressed in the search results, disulfide bond formation is crucial for the proper folding and function of many extracellular proteins, including toxins and virulence factors. In B. cereus, various enterotoxigenic genes (hblACD, nheABC, cytK, entFM, bceT, hlyII) and the emetic toxin gene (cesB) have been identified . The proper folding and stability of these toxins likely depend on correct disulfide bond formation. Therefore, bdbC1 could potentially influence B. cereus virulence by ensuring proper folding of secreted virulence factors, though direct experimental evidence would be needed to confirm this relationship.
What are the optimal conditions for recombinant expression of B. cereus bdbC1?
For recombinant expression of B. cereus proteins, Escherichia coli is frequently used as a heterologous host. Based on approaches used for other B. cereus proteins, the following methodology is recommended:
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Vector selection: A pET-based expression system with an N-terminal His-tag for purification is appropriate.
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E. coli strain: BL21(DE3) or Rosetta(DE3) strains are preferred, especially if the bdbC1 gene contains rare codons.
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Expression conditions: Initial induction with 0.5 mM IPTG at OD600 of 0.6-0.8, followed by expression at 25°C for 4-6 hours to minimize inclusion body formation.
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Buffer optimization: Since bdbC1 is involved in disulfide bond formation, the purification buffer should contain appropriate redox agents (e.g., DTT or β-mercaptoethanol) to maintain the protein in the desired redox state.
For purification analysis, techniques similar to those used for LysPBC1 can be employed, including SDS-PAGE under both reducing and non-reducing conditions to evaluate the presence of disulfide bonds .
What assays can be used to measure bdbC1 activity in vitro?
To evaluate bdbC1 enzymatic activity, the following assays can be employed:
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Disulfide oxidoreductase activity assay: Using model substrates such as insulin with turbidity measurements to monitor disulfide bond formation/reduction.
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Fluorescence-based redox assays: Utilizing fluorescent probes sensitive to changes in thiol/disulfide status.
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Coupled enzyme assays: Monitoring NADPH consumption during disulfide reduction reactions.
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Mass spectrometry-based approaches: Similar to those described for identifying disulfide-bonded proteins (DSBP), using sequential nonreducing/reducing two-dimensional SDS-PAGE combined with mass spectrometry .
For quantitative analysis, concentration-dependent hydrogen peroxide treatments can be used to assess how different oxidative conditions affect bdbC1 activity, as was done in studies of disulfide bond formation in cytosolic proteins .
How can researchers effectively analyze protein-protein interactions involving bdbC1?
To investigate protein-protein interactions involving bdbC1, several complementary approaches can be employed:
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Immunoaffinity purification coupled with mass spectrometry: Similar to the approach used for DBC1 protein interaction studies, this method involves creating a tagged version of bdbC1 (e.g., Flag-EGFP tag), expressing it in an appropriate cell system, and isolating interaction partners through immunoprecipitation followed by mass spectrometric identification .
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Yeast two-hybrid assays: To screen for potential interaction partners in a high-throughput manner.
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Surface plasmon resonance or isothermal titration calorimetry: For quantitative analysis of binding kinetics with putative partners.
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Crosslinking studies: Chemical crosslinking followed by mass spectrometry can capture transient interactions that might occur during the disulfide exchange reaction.
For validation of results, western blot analysis can be performed on 5-10% of whole cell lysate, cell pellet, flow-through, and eluates as described in the proteomic profiling methodology .
How does the structure of bdbC1 contribute to its substrate specificity?
The substrate specificity of disulfide formation proteins like bdbC1 is determined by several structural features:
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Active site architecture: The catalytic domain likely contains conserved cysteine residues that directly participate in the thiol-disulfide exchange reaction.
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Substrate binding groove: Structural elements surrounding the active site create a binding surface that determines which proteins can interact with bdbC1.
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Electrostatic surface properties: The distribution of charged residues influences protein-protein interactions and substrate recognition.
To investigate these structural features, researchers could employ X-ray crystallography or cryo-EM to solve the structure of bdbC1, potentially in complex with substrate proteins. Molecular dynamics simulations could further elucidate the dynamics of substrate binding and catalysis. Comparative analysis with disulfide bond formation proteins from other Bacillus species could highlight unique structural features that contribute to B. cereus-specific functions.
How is bdbC1 expression regulated in response to environmental stresses?
The regulation of bdbC1 expression likely responds to oxidative stress conditions, similar to other redox-sensitive systems. Based on studies of disulfide-bonded proteins, several regulatory mechanisms could be investigated:
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Transcriptional regulation: Quantitative PCR approaches similar to those used for DBC1 expression analysis can be applied to measure bdbC1 mRNA levels under various stress conditions .
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Redox-sensitive transcription factors: Identification of transcription factors that regulate bdbC1 expression in response to changing redox conditions.
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Post-translational modifications: Investigation of how oxidative stress might directly modify bdbC1 activity through post-translational modifications.
Experimental approaches could include exposing B. cereus cultures to varying hydrogen peroxide concentrations or altering the glutathione redox ratio, as these treatments have been shown to affect disulfide bond formation in proteins . Gene expression analysis using RT-qPCR with normalization to housekeeping genes like β-actin would provide quantitative data on expression changes .
What is the role of bdbC1 in B. cereus biofilm formation and persistence?
Disulfide bond formation proteins could potentially influence biofilm formation and persistence through several mechanisms:
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Extracellular matrix proteins: Proper folding of secreted proteins that form the biofilm matrix may depend on disulfide bonds.
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Cell surface adhesins: Many bacterial adhesins contain disulfide bonds that are crucial for their structure and function.
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Stress response: Biofilms often experience oxidative stress, where disulfide bond formation systems may play protective roles.
Research approaches could include creating bdbC1 knockout or knockdown strains of B. cereus and evaluating their biofilm-forming capacity using crystal violet staining, confocal microscopy, and biomass measurements. Complementation studies with wild-type bdbC1 would confirm phenotypic changes are specifically due to bdbC1 disruption.
How conserved is bdbC1 across different B. cereus strains and related Bacillus species?
The B. cereus group includes several closely related species with varying pathogenicity and ecological niches. Analyzing bdbC1 conservation could provide insights into its evolutionary significance:
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Sequence conservation analysis: Compare bdbC1 sequences across multiple B. cereus strains and related species using phylogenetic approaches similar to those applied to virulence gene profiling .
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Functional domain conservation: Identify conserved domains that are likely essential for disulfide formation activity versus variable regions that might confer strain-specific functions.
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Genomic context analysis: Examine whether bdbC1 is consistently associated with particular gene clusters across different strains.
What is the relationship between bdbC1 and related proteins in pathogenic versus non-pathogenic Bacillus species?
Comparing bdbC1 from pathogenic B. cereus strains with homologs from non-pathogenic Bacillus species could reveal adaptations related to virulence:
Researchers could investigate whether specific adaptations in bdbC1 correlate with the host range or virulence potential of different Bacillus species. This could involve recombinant expression of bdbC1 from different species and comparative functional assays to identify species-specific activities.
Could bdbC1 serve as a target for novel antimicrobial strategies against B. cereus infections?
Disulfide bond formation is crucial for the proper folding and function of many bacterial proteins, including virulence factors. Targeting bdbC1 could potentially disrupt multiple virulence mechanisms simultaneously:
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Inhibitor development: Small molecule inhibitors targeting the catalytic site of bdbC1 could prevent proper disulfide bond formation in virulence factors.
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Peptide-based approaches: Designed peptides that mimic bdbC1 substrates could competitively inhibit interactions with native substrates.
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Combination therapy: bdbC1 inhibitors could potentially sensitize B. cereus to existing antibiotics by compromising bacterial stress responses.
Research approaches could include high-throughput screening of chemical libraries for bdbC1 inhibitors, followed by evaluation of their effects on B. cereus growth, toxin production, and virulence in relevant models. Importantly, any therapeutic approach would need to consider the antibiotic resistance profiles of B. cereus strains, which show resistance to β-lactam antibiotics and rifampicin but susceptibility to ciprofloxacin, gentamicin, and chloramphenicol .
How does bdbC1 interact with the host immune system during infection?
Understanding how host immune systems recognize and respond to bacterial proteins like bdbC1 could inform vaccine development and immunomodulatory strategies:
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Pattern recognition receptor interactions: Investigate whether bdbC1 or its substrate proteins are recognized by host pattern recognition receptors.
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Antibody responses: Characterize antibody responses to bdbC1 in patients recovering from B. cereus infections.
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Cellular immunity: Examine T-cell responses to bdbC1 epitopes and their role in protective immunity.
Research methodologies could include ex vivo stimulation of human immune cells with purified recombinant bdbC1, followed by cytokine profiling and immunophenotyping. Animal models of B. cereus infection could be used to evaluate the protective potential of anti-bdbC1 immune responses.
What are common issues in purifying active recombinant bdbC1 and how can they be addressed?
Purification of functional disulfide formation proteins presents several technical challenges:
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Maintaining redox state: Since bdbC1 contains catalytic cysteines, maintaining the appropriate redox state during purification is crucial. Researchers should consider:
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Including reducing agents (DTT, TCEP) in purification buffers if the reduced form is desired
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Using oxidized/reduced glutathione mixtures to maintain specific redox potentials
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Performing purification under anaerobic conditions if necessary
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Solubility issues: If bdbC1 forms inclusion bodies:
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Lower expression temperature (16-20°C)
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Use solubility-enhancing fusion tags (SUMO, MBP, TrxA)
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Optimize induction conditions (lower IPTG concentration, 0.1-0.2 mM)
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Consider in vitro refolding protocols if necessary
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Activity preservation: To ensure purified bdbC1 retains activity:
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Minimize freeze-thaw cycles
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Store in appropriate buffer conditions with glycerol
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Consider storage under reducing conditions
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Similar approaches have been successful for the purification of enzymatically active LysPBC1 from B. cereus phage PBC1 .
How can researchers differentiate between the specific effects of bdbC1 and those of other disulfide formation proteins?
To establish specificity of bdbC1 function versus other disulfide formation proteins:
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Gene knockout/knockdown approaches: Create specific bdbC1 mutants while leaving other disulfide formation systems intact. Complementation studies with wild-type bdbC1 would confirm phenotypic specificity.
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Domain swapping experiments: Create chimeric proteins between bdbC1 and other disulfide formation proteins to map functional domains.
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Substrate identification: Use techniques like those described for identifying disulfide-bonded proteins to determine specific bdbC1 substrates versus those of other disulfide formation systems .
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Biochemical assays with purified components: Reconstitute disulfide formation reactions in vitro with purified components to measure specific activity of bdbC1 versus other related proteins.
These approaches would help establish the unique contribution of bdbC1 to B. cereus physiology and pathogenesis, distinguishing it from the effects of other related proteins.
How might systems biology approaches advance our understanding of bdbC1 function?
Systems biology offers powerful approaches to place bdbC1 in the broader context of B. cereus physiology:
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Interactome mapping: Global protein-protein interaction studies to identify the complete set of bdbC1 interaction partners under different conditions.
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Multi-omics integration: Combining transcriptomics, proteomics, and metabolomics data to understand how bdbC1 influences global cellular processes.
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Computational modeling: Creating predictive models of redox homeostasis that incorporate bdbC1 function.
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Network analysis: Identifying key nodes and pathways connected to bdbC1 function using protein interaction network analysis.
These approaches could reveal unexpected connections between disulfide bond formation and other cellular processes, potentially identifying novel regulatory mechanisms and therapeutic targets.
What are the prospects for applying CRISPR-Cas9 technology to study bdbC1 function?
CRISPR-Cas9 technology offers promising approaches for investigating bdbC1 function in B. cereus:
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Precise gene editing: Creating clean deletions, point mutations, or tagged versions of bdbC1 in its native genomic context.
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CRISPRi approaches: Using catalytically inactive Cas9 (dCas9) for targeted gene repression to create hypomorphic alleles of bdbC1.
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CRISPRa systems: Employing dCas9-based activation systems to upregulate bdbC1 expression.
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High-throughput screening: Using CRISPR libraries to identify genetic interactions with bdbC1.
Implementing CRISPR-Cas9 in B. cereus requires optimization of transformation protocols, appropriate promoters for Cas9 expression, and effective guide RNA designs. Researchers should consider potential off-target effects and implement appropriate controls, such as complementation with wild-type bdbC1 to confirm phenotype specificity.
