Recombinant Laodelphax striatella Carboxylic ester hydrolase (CarE)
Description
Biochemical Activity
CarE exhibits broad substrate specificity, hydrolyzing bonds including C-O, C-N, and C-C. While specific kinetic parameters (e.g., K<sub>m</sub>, V<sub>max</sub>) are not yet reported for the recombinant form, homologous ester hydrolases in insects demonstrate roles in:
Production Workflow
-
Cloning: The CarE gene is inserted into the pFast-HTB vector.
-
Transfection: Baculoviral vectors deliver the gene into High Five insect cells or E. coli for scalable expression .
-
Purification: Affinity chromatography via the His-tag ensures high yield (e.g., product code CSB-CF2219) .
Research Applications
-
Insecticide Resistance Studies: Ester hydrolases like CarE are implicated in metabolizing synthetic pesticides (e.g., imidacloprid) .
-
Viral Transmission Mechanisms: RSV infection upregulates energy metabolism genes (LsATPase, LsMIT13) in L. striatella , suggesting potential interplay with CarE in viral vector competence.
-
Structural Biology: Serves as a template for studying α/β-hydrolase folding and catalytic mechanisms .
Comparative Analysis with Related Enzymes
Knowledge Gaps and Future Directions
-
Substrate Specificity: Precise catalytic targets (e.g., phytosterols vs. synthetic esters) require validation.
-
In Vivo Role: RNAi knockdown studies could clarify CarE’s contribution to insecticide resistance or RSV transmission.
-
Structural Resolution: X-ray crystallography or cryo-EM would advance mechanistic studies.
Product Specs
Note: The complete sequence including tag sequence, target protein sequence and linker sequence could be provided upon request.
Q&A
What is Laodelphax striatella Carboxylic ester hydrolase (CarE) and what is its biological function?
Laodelphax striatella Carboxylic ester hydrolase (CarE) belongs to the broader family of carboxylesterases that catalyze the hydrolysis of ester bonds, producing a carboxylic acid and an alcohol. These enzymes typically hydrolyze esters, amides, thioesters, and carbamates . In insects like L. striatellus (small brown planthopper), CarEs play critical roles in various physiological processes including xenobiotic metabolism, juvenile hormone regulation, and potentially in diapause regulation.
The primary biochemical reaction catalyzed by CarE can be represented as:
R-COOR' + H₂O → R-COOH + R'-OH
This hydrolysis reaction increases the polarity of compounds, typically enhancing their water solubility and facilitating their elimination or further metabolism. While human carboxylesterases are well-characterized in drug metabolism pathways , insect CarEs like those from L. striatellus have distinct evolutionary adaptations related to their ecological niche.
What expression systems are most effective for producing recombinant Laodelphax striatella CarE?
Based on research methodologies used for similar enzymes, several expression systems have proven effective for recombinant CarE production:
| Expression System | Advantages | Considerations | Typical Yield |
|---|---|---|---|
| E. coli (pET-22b(+)) | High yield, rapid growth, well-established protocols | May require optimization of codon usage, potential inclusion body formation | 10-50 mg/L culture |
| E. coli (pCR-XL-TOPO) | Good for large insert genes, stable cloning | Variable expression levels | 5-30 mg/L culture |
| Baculovirus-insect cell | Post-translational modifications similar to native enzyme | Higher cost, longer production time | 5-20 mg/L culture |
The selection of an appropriate expression system should be guided by specific research objectives. For basic biochemical characterization, E. coli-based systems using vectors like pET-22b(+) are frequently employed, as evidenced by successful expression of analogous carboxylic ester hydrolases from other organisms . For more complex studies requiring proper folding and post-translational modifications, insect cell expression systems may be preferable despite their higher cost and complexity.
Purification typically involves a combination of affinity chromatography (often using His-tag constructs), ion-exchange chromatography, and size exclusion techniques to achieve high purity and yield.
How does temperature affect Laodelphax striatella CarE expression and activity?
Temperature significantly influences both the expression of CarE in L. striatellus and the enzymatic activity of the recombinant protein. Research on L. striatellus has demonstrated that temperature is a critical factor affecting the insect's physiology, with notable impacts on diapause induction and population dynamics .
For the native organism, temperature effects include:
-
High temperatures (33°C) significantly affect L. striatellus reproduction and survival rates
-
Temperature modulates diapause induction, with diapause almost completely abrogated at 28°C
-
Critical physiological processes are temperature-dependent, suggesting that CarE expression may similarly vary with temperature
For recombinant CarE enzyme activity:
-
Temperature stability (T₅₀) values for similar carboxylic ester hydrolases range from 56-58°C
-
Optimal temperature for activity typically falls between 30-40°C for most characterized insect CarEs
-
Activity assays should consider temperature as a critical parameter to optimize enzymatic performance
When designing experiments with recombinant L. striatellus CarE, researchers should carefully control temperature during both expression and activity measurements to ensure reproducible results.
How does the organic solvent tolerance of Laodelphax striatella CarE compare to other insect carboxylesterases?
Organic solvent tolerance is a valuable property for biotechnological applications of enzymes. While specific data on L. striatellus CarE is limited in the provided search results, comparative analysis with other characterized carboxylic ester hydrolases provides insight into potential tolerance profiles:
For researchers investigating L. striatellus CarE, systematic evaluation of organic solvent tolerance could reveal unique properties compared to other insect carboxylesterases. Several characterized CEs show unexpected "activation" in the presence of organic solvents, such as CE13 from P. aestusnigri displaying higher activity in 50% acetonitrile than in aqueous solution alone .
Methodology for evaluating organic solvent tolerance should include:
-
Initial screening using common organic solvents at varying concentrations (10-50%)
-
Determination of half-inactivation temperature (T₅₀) values in the presence of different solvents
-
Kinetic parameter analysis (Km, kcat) with and without organic solvents
-
Long-term stability assessments in solvent systems
These approaches would help position L. striatellus CarE in the spectrum of solvent-tolerant biocatalysts and identify potential biotechnological applications.
What structural and functional characteristics influence substrate specificity of Laodelphax striatella CarE?
Understanding substrate specificity is crucial for both fundamental research and applied studies of L. striatellus CarE. While specific structural data for this enzyme is not provided in the search results, general principles and comparative analysis can guide research in this area:
Factors influencing CarE substrate specificity include:
-
Active site architecture: The size and shape of the substrate binding pocket determines accommodation of different substrates
-
Catalytic triad composition: The specific amino acids in the catalytic triad affect reaction chemistry
-
Binding pocket hydrophobicity: The distribution of hydrophobic/hydrophilic residues influences substrate preference
-
Surface loops and gating mechanisms: Dynamic elements can control substrate access
For experimental investigation of substrate specificity, researchers typically employ:
| Approach | Advantages | Limitations | Key Considerations |
|---|---|---|---|
| Homology modeling | Predicts structure based on similar enzymes | Accuracy depends on template quality | Requires validation through experimental data |
| Site-directed mutagenesis | Directly tests the role of specific residues | Labor-intensive | Selection of target residues requires careful analysis |
| Substrate screening panels | Provides direct experimental evidence | Limited to available substrates | Should include structurally diverse compounds |
| Kinetic parameter determination | Quantifies specificity constants | Time-consuming | Critical for comparing specificities rigorously |
For L. striatellus CarE, researchers might consider testing activity against substrates like 2-coumaranone, 2H-chromen-2-one, and 2H-chromen-7-ol, which have been used to characterize other carboxylic ester hydrolases and represent compounds with varying structural complexity and water solubility .
How do photoperiod and temperature interact to regulate CarE expression in Laodelphax striatellus during different life stages?
The small brown planthopper (L. striatellus) exhibits complex physiological responses to environmental cues, particularly photoperiod and temperature. These factors critically influence the insect's diapause induction and termination , suggesting potential regulatory effects on CarE expression.
Key research findings on photoperiod-temperature interactions in L. striatellus include:
-
Critical daylength for diapause induction varies with temperature: approximately 11h at 25°C, 12h at 22°C and 20°C, and 12.5h at 18°C
-
The third instar nymph stage shows the highest sensitivity to photoperiodic signals
-
Temperature-photoperiod interactions determine seasonal population dynamics, with numbers dropping sharply in summer and reviving quickly in autumn
The relationship between these environmental factors and CarE expression represents an important research direction. Methodological approaches to investigate this relationship should include:
-
Quantitative PCR analysis of CarE gene expression under controlled temperature-photoperiod regimes
-
Enzyme activity assays across developmental stages and environmental conditions
-
Comparative proteomics to identify co-regulated enzymes and pathways
-
Field sampling coupled with laboratory analyses to validate experimental findings
Understanding these regulatory mechanisms could provide insights into both basic insect physiology and potential targets for pest management strategies.
What high-throughput screening methods are most effective for characterizing recombinant Laodelphax striatella CarE?
High-throughput screening (HTS) methods enable efficient characterization of enzyme properties across multiple conditions. For recombinant L. striatellus CarE, several approaches have proven valuable for similar enzymes:
A particularly useful approach described for carboxylic ester hydrolases involves perforation of E. coli cells expressing the enzyme using polymyxin B, followed by semi-automated transfer of cell lysates into assay plates using multi-channel pipetting systems . This method enables rapid screening without the need for individual enzyme purification steps.
For substrate screening, p-nitrophenyl acetate provides a convenient colorimetric readout, though more specialized substrates may better reflect the natural activity profile of L. striatellus CarE. For screening activity against water-insoluble substrates, specialized approaches integrating organic solvents may be necessary .
What are effective strategies for improving the catalytic efficiency of Laodelphax striatella CarE through protein engineering?
Protein engineering offers powerful approaches to enhance the properties of recombinant enzymes for research and biotechnological applications. For L. striatellus CarE, several strategies could be employed:
-
Rational design approaches:
-
Site-directed mutagenesis targeting active site residues
-
Introduction of stabilizing disulfide bridges
-
Modification of surface charges to improve solubility
-
-
Directed evolution strategies:
-
Error-prone PCR for random mutagenesis
-
DNA shuffling with related CarE genes
-
Combinatorial active site saturation testing (CAST)
-
-
Semi-rational approaches:
-
Consensus sequence analysis
-
Ancestral sequence reconstruction
-
Hot spot identification followed by saturation mutagenesis
-
Success in protein engineering requires careful selection of screening methods that accurately reflect the desired property improvements. For example, if enhancing organic solvent tolerance is the goal, high-throughput assays that measure activity in the presence of relevant solvents would be essential .
When comparing engineered variants, comprehensive characterization should include:
-
Determination of kinetic parameters (kcat, Km, kcat/Km)
-
Stability assessments (half-life at elevated temperatures, pH stability)
-
Structural analysis where possible (circular dichroism, fluorescence spectroscopy)
-
Substrate specificity profiles using diverse substrate panels
How can researchers effectively scale up production of recombinant Laodelphax striatella CarE for structural studies?
Structural studies such as X-ray crystallography and cryo-electron microscopy require substantial quantities of highly pure, homogeneous protein. Scaling up production of recombinant L. striatellus CarE presents several challenges that can be addressed through systematic optimization:
| Production Stage | Key Considerations | Optimization Strategies | Quality Control Metrics |
|---|---|---|---|
| Expression vector design | Codon optimization, fusion tags | Codon adaptation to expression host, cleavable tags | Sequence verification, expression level testing |
| Host selection | Growth characteristics, post-translational capabilities | Testing multiple E. coli strains or alternative hosts | Yield comparison, solubility assessment |
| Culture conditions | Media composition, induction parameters | DOE approach to optimize temperature, inducer concentration, timing | Growth curves, protein yield per biomass |
| Cell lysis | Extraction efficiency, protein stability | Buffer optimization, protease inhibitor selection | Total protein recovery, activity preservation |
| Purification | Yield, purity, homogeneity | Multi-step chromatography development | SDS-PAGE, activity assays, DLS for homogeneity |
For successful structural studies, protein quality is often more critical than absolute quantity. Researchers should focus on:
-
Removing heterogeneity through additional purification steps
-
Assessing protein stability and monodispersity using dynamic light scattering (DLS)
-
Performing limited proteolysis to identify stable domains if the full-length protein proves challenging
-
Utilizing thermal shift assays to identify stabilizing buffer conditions
Based on approaches used for similar enzymes, expression in E. coli using vectors like pET-22b(+) has proven successful for many carboxylic ester hydrolases . For L. striatellus CarE, exploring tags beyond the standard His-tag (such as MBP fusion for enhanced solubility) may improve yield and quality for structural studies.
How might comparative genomics inform our understanding of Laodelphax striatella CarE evolution and function?
Comparative genomic approaches offer powerful insights into enzyme evolution and functional specialization. For L. striatellus CarE, several research directions could yield valuable information:
-
Phylogenetic analysis across insect orders to trace evolutionary history
-
Identification of selection pressures on CarE genes in plant-feeding insects
-
Comparison of CarE diversity between L. striatellus and other planthopper species
-
Analysis of gene duplication events and subsequent functional divergence
Researchers could construct comprehensive phylogenetic trees including CarE sequences from:
-
Multiple insect orders
-
Agricultural pest species with different feeding habits
-
Species with documented insecticide resistance
Such comparative analysis would help position L. striatellus CarE within the broader evolutionary context of insect carboxylesterases and potentially reveal adaptations specific to the small brown planthopper's ecological niche.
What is the potential role of Laodelphax striatella CarE in mediating temperature adaptation and seasonal rhythms?
Given the established effects of temperature on L. striatellus population dynamics and diapause regulation , investigating the potential involvement of CarE in temperature adaptation represents an intriguing research direction.
Evidence suggesting CarE involvement in temperature adaptation includes:
-
Temperature-dependent activity profiles observed in carboxylesterases from other organisms
-
The significant impact of temperature on L. striatellus reproduction and survival
-
The regulatory role of temperature in diapause induction and termination
Research methodologies to explore this connection could include:
-
Quantifying CarE expression levels across temperature gradients using qPCR
-
Comparing CarE activity in populations from different climatic regions
-
Examining seasonal variations in CarE expression in field populations
-
Investigating the effects of temperature shifts on CarE expression and activity
Understanding the potential role of CarE in temperature adaptation could provide valuable insights into insect physiology and potential mechanisms of climate change response in agricultural pest species.
