Recombinant Populus trichocarpa Apocytochrome f (petA)
Description
Overview
Recombinant Populus trichocarpa Apocytochrome f (petA) is a protein derived from the Populus trichocarpa, also known as the Western balsam poplar . PetA is a component of the cytochrome b6f complex, essential for photosynthetic electron transfer in plants . The "apocytochrome" form refers to the protein without its heme cofactor . Recombinant production involves synthesizing the protein using genetically engineered cells, providing a means to study its structure, function, and interactions .
Isolation and Characterization of Phytochemicals from Populus Trichocarpa
Populus trichocarpa, and related species, are known to contain various phytochemicals with potential therapeutic properties . Research has focused on isolating and characterizing these compounds to understand their biochemical profiles and pharmacological activities .
Table 1: HPLC Quantitative Analysis of Phytochemicals in Populus Species
| Compound | P. trichocarpa (Leaves) | P. alba (Leaves) | P. glandulosa (Leaves) |
|---|---|---|---|
| Salicin (1) | High | Low | Medium |
| Populin (3) | High | Low | Medium |
| Salireposide (2) | Medium | Low | High |
| Rutin (6) | High | Medium | Low |
| Narcissin (7) | High | Low | Medium |
| Thermopsoside (4) | Medium | High | Low |
| Cynaroside (5) | Low | Medium | High |
Future Directions
Further research on Recombinant Populus trichocarpa Apocytochrome f (petA) could explore:
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The detailed mechanisms of PetA involvement in the electron transfer process .
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The regulation of petA gene expression under various environmental conditions .
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The potential for manipulating PetA to improve photosynthetic efficiency and plant productivity .
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The role of associated phytochemicals in the defense responses of Populus trichocarpa .
Product Specs
Note: While we prioritize shipping the format currently in stock, please specify your format preference during order placement for customized preparation.
Note: Our proteins are shipped with standard blue ice packs. Dry ice shipping requires prior arrangement and incurs additional charges.
The tag type is determined during production. If you require a specific tag, please inform us for preferential development.
Target Background
Component of the cytochrome b6-f complex. This complex mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions.
KEGG: pop:Poptr_cp036
Q&A
What is Apocytochrome f and what is its role in Populus trichocarpa?
Apocytochrome f is the precursor form of cytochrome f, a crucial component of the cytochrome b6f complex in the chloroplast electron transport chain of photosynthesis. In Populus trichocarpa, the petA gene encodes this protein, which plays an essential role in mediating electron transfer between photosystem II and photosystem I. Unlike many small secreted proteins that function in plant-microbe interactions , cytochrome f is primarily involved in the plant's energy metabolism pathways. The protein contains a heme group that facilitates electron transfer and is anchored to the thylakoid membrane, with most of the protein exposed to the lumen.
How does the genome structure of Populus trichocarpa influence recombinant protein studies?
The Populus trichocarpa genome has been fully sequenced and contains 19 chromosomes with extensive genetic diversity across its range. This diversity creates both challenges and opportunities for recombinant protein studies. Research has identified approximately 7.4 million small genetic variants across the P. trichocarpa germplasm, with about 377,000 non-synonymous variants that could potentially affect protein structure and function . When designing recombinant protein studies, researchers must consider this genetic diversity, as sequence variations may impact protein expression, structure, and function. High-resolution genetic mapping has also revealed recombination hotspots and sex-biased inheritance patterns that may affect gene expression .
What expression systems are most effective for producing recombinant Populus proteins?
For recombinant expression of Populus trichocarpa proteins, several expression systems have proven effective, with selection depending on research objectives:
| Expression System | Advantages | Limitations | Best Used For |
|---|---|---|---|
| E. coli | Rapid growth, high yield, cost-effective | Limited post-translational modifications, inclusion body formation | Initial structural studies, antibody production |
| Yeast (P. pastoris) | Eukaryotic post-translational modifications, secretion possible | Longer expression time, different codon usage | Functional studies requiring proper folding |
| Insect cells | Complex eukaryotic modifications, membrane protein expression | Higher cost, specialized equipment | Complex proteins with multiple domains |
| Plant-based systems | Native-like modifications, proper folding | Lower yield, longer production time | Functional studies requiring authentic modifications |
When expressing chloroplast proteins like Apocytochrome f, removing transit peptides and optimizing codon usage for the host organism significantly improves expression efficiency.
How can I optimize experimental conditions for functional analysis of recombinant Populus trichocarpa Apocytochrome f?
Functional analysis of recombinant Apocytochrome f requires careful consideration of protein maturation conditions. Since native cytochrome f requires heme incorporation and proper folding, consider these methodological approaches:
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Express the protein without its transit peptide to improve solubility
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Co-express with heme lyase or supplement with hemin during purification
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Use mild detergents (0.1-0.5% n-dodecyl β-D-maltoside) to maintain native-like membrane protein conformation
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Employ anaerobic conditions during purification to prevent oxidative damage
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Validate functionality through electron transfer assays using artificial electron donors/acceptors
Research has demonstrated that plant proteins can be successfully expressed in heterologous systems and maintain their biological activity when proper conditions are established . For instance, similar approaches have been used to study small secreted proteins from Populus, with experimental evidence showing that they can enter fungal hyphae and accumulate in the nucleus .
How do genetic variants in the petA gene across Populus trichocarpa populations affect protein function?
Studies examining genomic diversity in Populus trichocarpa have identified numerous genetic variants across individual genomes . While specific petA variants haven't been comprehensively characterized, research approaches should consider:
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Population-wide sequence analysis of the petA locus to identify non-synonymous variants
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Prediction of functional effects using structural modeling
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Experimental validation through site-directed mutagenesis of recombinant proteins
A comparison of variant effects could follow the approach used in P. trichocarpa diversity studies, where stringent quality filtering improved genetic variant identification . Both rare and common alleles should be analyzed, as rare genetic variants have been shown to potentially explain significant portions of phenotypic variability in P. trichocarpa .
What genomic resources are available for studying recombinant Populus trichocarpa proteins?
Several high-quality genomic resources support research on recombinant Populus proteins:
| Resource Type | Description | Application to Recombinant Protein Studies |
|---|---|---|
| Reference Genome | P. trichocarpa v3.0 with high-confidence gene models | Identification of target sequences including regulatory elements |
| Resequenced Genomes | 1,014 pure P. trichocarpa entire genomes | Analysis of natural variants affecting protein structure/function |
| Genetic Maps | 14 high-fidelity maps with 19 linkage groups | Understanding inheritance patterns of protein-coding genes |
| Variant Databases | 7.4M high-confidence genetic variants | Selection of representative alleles for recombinant expression |
These resources were developed using sophisticated bioinformatic pipelines combining multiple variant calling methods (Platypus and HaplotypeCaller) to ensure high confidence in identified variants . For recombinant protein studies, these resources allow identification of the most common allelic variants and potential functional impacts of sequence differences.
What purification strategies are most effective for recombinant Populus trichocarpa Apocytochrome f?
Purification of recombinant Apocytochrome f presents unique challenges due to its membrane association and cofactor requirements. A successful purification strategy includes:
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Extraction optimization: Use of specialized detergents (0.5-1% n-dodecyl β-D-maltoside or 1-2% digitonin) to solubilize membrane-associated proteins
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Affinity chromatography: Employ N-terminal or C-terminal tags (His6, Strep-tag II) positioned to avoid interference with heme binding
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Ion exchange chromatography: As a secondary purification step, using the protein's predicted isoelectric point to determine optimal buffer conditions
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Size exclusion chromatography: Final polishing step to remove aggregates and ensure homogeneous preparation
For experimental validation of protein entry into target tissues, similar approaches to those used with Populus SSPs could be implemented, such as using FITC-labeled purified proteins to track localization . These methods have successfully demonstrated that plant-derived small proteins can cross fungal hyphal membranes and accumulate within the fungal nucleus .
How can I assess the structural integrity and functionality of recombinant Populus trichocarpa Apocytochrome f?
Multiple complementary techniques should be employed to verify both structural integrity and functional activity:
| Assessment Type | Techniques | Parameters to Measure |
|---|---|---|
| Secondary Structure | Circular Dichroism (CD) | α-helical content (expected ~30-40%) |
| Tertiary Structure | Thermal Shift Assay | Melting temperature (Tm) |
| Cofactor Binding | UV-Visible Spectroscopy | Soret band (~420 nm) and α/β bands (520-550 nm) |
| Redox Activity | Cyclic Voltammetry | Midpoint potential (Em) |
| Electron Transfer | Cytochrome c reduction assay | Kinetic rate constants |
When interpreting results, comparison with native chloroplast-derived cytochrome f provides important benchmarks. Successful reconstitution would show spectroscopic properties consistent with proper heme incorporation and redox potential values within the physiological range for the electron transport chain.
How can cross-species comparative analysis enhance understanding of recombinant Populus trichocarpa Apocytochrome f?
Leveraging comparative genomics approaches can provide valuable insights into conserved functional domains and species-specific adaptations in Apocytochrome f. Studies comparing genetic diversity and recombination patterns across Populus species offer a framework for such analyses:
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Align petA sequences from multiple species to identify conserved domains
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Map non-synonymous variants to structural models to predict functional impacts
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Examine recombination patterns near the petA locus in different populations
Cross-species comparisons may reveal selection pressures on specific protein domains. For instance, research on P. trichocarpa has shown sex-biased recombination patterns on 8 out of 19 chromosomes , which may influence the evolution of genes located in these regions. Similarly, intraspecific variation in recombination rates correlates with genomic features such as gene density and GC content , potentially affecting the evolutionary trajectory of photosynthetic proteins.
How can protein-protein interaction studies enhance our understanding of recombinant Populus trichocarpa Apocytochrome f function?
Cytochrome f functions within a complex protein network in the thylakoid membrane. Interaction studies can reveal:
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Direct binding partners within the cytochrome b6f complex
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Transient interactions with electron donors/acceptors (plastocyanin, photosystem II components)
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Assembly factors that facilitate proper integration into the thylakoid membrane
Methodological approaches include:
| Technique | Application | Advantages |
|---|---|---|
| Pull-down assays | Identify stable interactors | Works with detergent-solubilized membrane proteins |
| Surface Plasmon Resonance | Measure binding kinetics | Provides quantitative Kon/Koff rates |
| Förster Resonance Energy Transfer | Verify interactions in vivo | Detects proximity in native-like environment |
| Crosslinking Mass Spectrometry | Map interaction interfaces | Identifies specific contact residues |
These approaches can be informed by techniques used to study protein localization and function in Populus, such as those employed to track SSP movement and nuclear localization in symbiotic interactions .
What are the key challenges in scaling up production of recombinant Populus trichocarpa Apocytochrome f for structural studies?
Structural studies typically require milligram quantities of highly pure, homogeneous protein. For membrane proteins like Apocytochrome f, key challenges include:
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Expression yield: Membrane proteins often express at lower levels than soluble proteins
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Proper folding: Ensuring correct insertion of the heme cofactor
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Homogeneity: Obtaining a single conformational state suitable for crystallization
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Stability: Maintaining protein integrity during concentration and crystallization
Strategies to address these challenges include:
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Screen multiple expression constructs with varying truncations and fusion partners
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Optimize media composition to include additives that promote heme incorporation
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Employ nanodiscs or amphipols as alternatives to detergents for membrane protein stabilization
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Use controlled proteolysis to remove flexible regions that may hinder crystallization
For integrative structural approaches, combining X-ray crystallography with small-angle X-ray scattering (SAXS) and cryo-electron microscopy can provide complementary structural information at different resolutions.
How should researchers interpret conflicting functional data from different recombinant expression systems?
When studying Populus trichocarpa Apocytochrome f, researchers may encounter discrepancies between results obtained from different expression systems. A systematic approach to resolving these conflicts includes:
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Compare protein sequence integrity between expression systems (N-terminal processing, post-translational modifications)
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Analyze spectroscopic properties to confirm proper heme incorporation
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Evaluate membrane/detergent composition effects on protein activity
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Consider expression host-specific factors that might influence folding
The interpretation should consider that native cytochrome f functions in a specific lipid environment within the thylakoid membrane. Results that most closely match the properties of the native protein extracted directly from Populus chloroplasts should generally be given greater weight when conflicts arise.
What bioinformatic tools are most appropriate for analyzing sequence-structure-function relationships in Populus trichocarpa Apocytochrome f variants?
Several computational approaches can predict how sequence variants might affect protein structure and function:
| Analysis Type | Recommended Tools | Application |
|---|---|---|
| Homology Modeling | SWISS-MODEL, Phyre2 | Generate structural models based on crystallized cytochrome f from other species |
| Molecular Dynamics | GROMACS, NAMD | Simulate conformational changes and stability of variants |
| Binding Site Analysis | CASTp, POCASA | Identify potential alterations in interaction surfaces |
| Evolutionary Analysis | ConSurf, PAML | Map conservation patterns to infer functional importance |
How can RNA-seq data enhance our understanding of petA expression patterns in different tissues and conditions?
RNA-sequencing data can provide valuable insights into the expression dynamics of the petA gene, informing recombinant protein studies:
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Expression levels: Quantify transcript abundance across tissues, developmental stages, and stress conditions
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Splicing variants: Identify potential alternative transcripts that might encode protein variants
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Co-expression networks: Identify genes with similar expression patterns that may function in related processes
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Response to environmental factors: Determine how environmental conditions affect petA expression
Similar RNA-seq approaches have been successfully applied to study P. trichocarpa genes during mycorrhizal symbiosis, where quantitative expression was validated by RT-PCR analysis of selected transcripts . For petA expression analysis, special attention should be paid to photosynthetic tissues and developmental stages with changing chloroplast abundance.
