Recombinant Neosartorya fumigata Plasma membrane fusion protein prm1 (prm1)
Description
Functional Role in Membrane Fusion
Prm1 is critical for plasma membrane fusion during fungal mating and hyphal development:
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Mechanism: Facilitates bilayer fusion by reducing membrane tension and preventing lysis during mating .
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Calcium Dependence: In Saccharomyces cerevisiae, Prm1 mutants exhibit increased lysis under low Ca²⁺ conditions, suggesting Ca²⁺-dependent repair mechanisms .
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Pathogenicity: In Aspergillus fumigatus, homologs like HscA interact with host proteins (e.g., human p11) to evade phagosomal degradation, enabling fungal survival .
Biotechnological Applications
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Serodiagnosis: Recombinant Prm1 homologs (e.g., Afmp1p in A. fumigatus) are antigenic and used to detect antibodies in aspergillosis patients .
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Protein Engineering: His/Fc/Avi-tagged versions enable structural studies and host-pathogen interaction analyses .
Table 2: Comparison of Prm1 Homologs Across Species
| Species | Protein Name | Function | Pathogenicity Role |
|---|---|---|---|
| Neosartorya fumigata | Prm1 | Membrane fusion, hyphal growth | Evasion of phagosome maturation |
| Saccharomyces cerevisiae | Prm1 | Mating, membrane integrity | N/A |
| Aspergillus clavatus | Prm1 | Structural protein | Not characterized |
Research Findings and Clinical Relevance
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Immune Evasion: A. fumigatus HscA (a Prm1 homolog) binds human p11 to redirect phagosomes away from lysosomal degradation, facilitating fungal escape .
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Genetic Polymorphism: A single nucleotide polymorphism (SNP) in the human S100A10 (p11) gene correlates with susceptibility to invasive aspergillosis .
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Enzymatic Activity: Alpha-1,2-mannosyltransferase homologs (e.g., AFUA_5G12160 in N. fumigata) contribute to cell wall biosynthesis, impacting virulence .
Expression and Purification Challenges
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Yield: Low abundance in native A. fumigatus necessitates heterologous expression for large-scale production .
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Stability: Requires glycerol (5–50%) and strict storage at –80°C to prevent aggregation .
Future Directions
Product Specs
Note: We prioritize shipping the format currently in stock. However, if you have specific format requirements, please indicate them in your order. We will accommodate your request as best as possible.
Note: All proteins are shipped with standard blue ice packs by default. If you require dry ice shipping, please notify us in advance. Additional fees will apply.
Generally, the shelf life of liquid form is 6 months at -20°C/-80°C. The shelf life of lyophilized form is 12 months at -20°C/-80°C.
Target Background
Q&A
What is Neosartorya fumigata and how does it relate to Aspergillus fumigatus?
Neosartorya fumigata is the teleomorph (sexual stage) of Aspergillus fumigatus, one of the most ubiquitous airborne saprophytic fungi. A. fumigatus plays an essential role in recycling environmental carbon and nitrogen, primarily residing in soil where it grows on organic debris . While these two names technically refer to different life stages of the same organism, taxonomic debates have led researchers to analyze distinct molecular characteristics.
DNA-DNA reassociation studies show values higher than 92% for strains of A. fumigatus, while values lower than 70% have been calculated between A. fumigatus and Neosartorya species, indicating genetic distinctions . The sequencing of internally transcribed spacers (ITS1 and ITS2) of ribosomal DNA provides sufficient differences to distinguish between Neosartorya species and A. fumigatus .
What molecular techniques are most reliable for identifying the prm1 gene in Neosartorya fumigata?
Multiple molecular approaches can reliably identify the prm1 gene in Neosartorya fumigata, each with specific advantages:
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PCR-based methods with primers designed from conserved regions offer a starting point for identification, though primers must be carefully selected to distinguish between closely related species .
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DNA sequencing approaches, particularly whole gene sequencing of prm1 including introns, provide definitive identification. Introns often show greater variability than coding regions, offering enhanced discriminatory power .
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Restriction Fragment Length Polymorphism (RFLP) analysis, especially when combined with Southern blot hybridization using species-specific probes, provides characteristic patterns for identification .
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Microsatellite analysis offers high reproducibility and discriminatory power for strain identification. Four CA repeats identified in Aspergillus genome—(CA)9(GA)25, (CA)2C(CA)23, (CA)8, and (CA)21—have proven particularly useful .
For comprehensive characterization, researchers should employ a combination of these methods rather than relying on a single approach.
How do researchers extract and purify membrane fusion proteins like prm1 while maintaining functional integrity?
Extracting and purifying membrane fusion proteins like prm1 presents significant challenges due to their hydrophobic domains and complex topologies. A methodological approach that preserves functional integrity requires consideration of:
Table 1. Systematic Approach to prm1 Extraction and Purification
| Stage | Methodology | Critical Considerations |
|---|---|---|
| Expression System | Eukaryotic systems (e.g., Pichia pastoris) | Better post-translational modifications; closer to native environment |
| Cell Disruption | Enzymatic spheroplasting; mechanical disruption at low temperatures | Gentle methods preserve structure; protease inhibitors prevent degradation |
| Membrane Extraction | Detergent screening (DDM, LMNG, digitonin) | Optimal detergent concentration must balance extraction efficiency and protein stability |
| Purification | Affinity chromatography followed by size exclusion | Tagged constructs facilitate purification; size exclusion removes aggregates |
| Functional Verification | Liposome fusion assays; circular dichroism | Confirmation of both structure and activity ensures proper folding |
Recent advances in native nanodiscs and saposin-lipoprotein nanoparticles provide alternative approaches for maintaining membrane proteins in a native-like lipid environment during purification, potentially preserving functional domains critical for membrane fusion activity.
How can experimental design principles be applied to optimize recombinant prm1 expression?
Optimizing recombinant prm1 expression requires a systematic Design of Experiments (DOE) approach that identifies and modulates key variables affecting protein yield and functionality . The experimental design should follow a factorial structure to efficiently explore interactions between variables.
Table 2. Factorial Design for prm1 Expression Optimization
| Factor | Low Level | High Level | Considerations |
|---|---|---|---|
| Host Strain | E. coli BL21(DE3) | Pichia pastoris | Eukaryotic hosts better accommodate membrane proteins |
| Vector Design | Constitutive promoter | Inducible promoter | Tight regulation may mitigate toxicity |
| Induction Temperature | 16°C | 30°C | Lower temperatures often improve folding |
| Inducer Concentration | 0.1 mM IPTG | 1.0 mM IPTG | Optimal concentration balances expression and toxicity |
| Media Composition | Minimal media | Rich media | Complex media provides additional cofactors |
| Expression Time | 4 hours | 24 hours | Extended times may increase yield but risk degradation |
For membrane proteins like prm1, particular attention must be paid to factors affecting membrane integration and folding. Response surface methodology (RSM) can subsequently refine the most significant factors identified in the initial factorial design .
Key considerations specific to prm1 include:
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The incorporation of fusion partners that enhance solubility
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The selection of detergents compatible with downstream applications
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The maintenance of glycosylation patterns if required for function
Control variables such as cell density at induction, oxygen transfer rates, and pH must be standardized across experiments to ensure reliable comparisons .
What are the challenges in distinguishing between prm1 homologs in Neosartorya fumigata and closely related species?
The distinction between prm1 homologs in Neosartorya fumigata and closely related species presents several analytical challenges:
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Taxonomic ambiguity between Aspergillus fumigatus and Neosartorya species complicates precise classification of gene sequences .
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High genetic similarity within A. fumigatus strains (>92% in DNA-DNA reassociation studies) but lower values (<70%) between A. fumigatus and Neosartorya species creates a complex identification landscape .
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Functional constraints often result in conserved domains, making it difficult to distinguish between prm1 homologs from closely related species.
To address these challenges, researchers should implement:
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Multi-locus sequence typing that analyzes multiple genetic loci beyond prm1
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Analysis of intron sequences, which show greater variability than coding regions
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Microsatellite analysis, which has demonstrated high discriminatory power in strain typing
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Restriction fragment analysis using species-specific probes
The AFUT1 retrotransposon sequence, a defective element bounded by long terminal repeats (LTRs) of 282 bp, has proven particularly useful for strain fingerprinting in A. fumigatus . Hybridization with this sequence provides unique and highly discriminative Southern blot patterns for each strain tested.
How can contradictory results in prm1 functional studies be reconciled through improved experimental approaches?
Contradictions in prm1 functional studies often arise from variations in experimental systems, strain differences, and methodological inconsistencies. A systematic approach to reconciling these contradictions should include:
Table 3. Methodology for Resolving Contradictory prm1 Results
| Approach | Implementation | Expected Outcome |
|---|---|---|
| Standardization | Use reference strains; establish consistent growth conditions | Reduces variability from strain differences and culture conditions |
| Complementation | Cross-species gene transfer; domain swapping experiments | Identifies functional conservation and critical domains |
| Comprehensive Phenotyping | Multiple assays to assess function; quantitative measurements | Reveals context-dependent functions that explain discrepancies |
| Structural Analysis | Determination of protein structure in different conditions | Provides mechanistic insight into functional variations |
| Meta-analysis | Systematic review of published studies; statistical integration of results | Identifies patterns and sources of variation across studies |
When contradictory results persist despite these approaches, researchers should consider:
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The possibility that prm1 function varies depending on environmental conditions or developmental stage
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Potential interactions with species-specific binding partners that modify function
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Post-translational modifications that differ between experimental systems
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The existence of compensatory mechanisms that mask phenotypes in some genetic backgrounds
By systematically exploring these possibilities through controlled experiments, researchers can develop a more nuanced understanding of prm1 function that accommodates seemingly contradictory observations.
What DNA analysis techniques provide the most definitive characterization of the prm1 gene across fungal species?
Based on the literature on Aspergillus/Neosartorya molecular characterization, several DNA analysis techniques provide definitive characterization of the prm1 gene:
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Whole gene sequencing remains the gold standard, capturing both coding regions and introns, which can show greater variability even when protein sequences are conserved .
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Microsatellite analysis offers high discriminatory power and reproducibility. Four CA repeats identified in the Aspergillus genome have proven particularly useful for strain typing .
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RFLP analysis combined with Southern blot hybridization using the AFUT1 retrotransposon as a probe provides unique fingerprinting patterns for strain identification .
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Next-generation sequencing approaches enable comprehensive genomic analysis, revealing not only the prm1 sequence but also its genomic context and potential regulatory elements.
The defective retrotransposon element AFUT1 (6.9 kb bounded by two long terminal repeats of 282 bp) has become particularly valuable for strain typing due to its species-specificity and the existence of approximately 10 copies in the A. fumigatus genome .
For the most comprehensive characterization, researchers should combine methods that assess sequence identity (direct sequencing), genomic context (next-generation sequencing), and strain-specific variations (microsatellite analysis or AFUT1 hybridization).
How can CRISPR-Cas9 be optimized for studying prm1 function in Neosartorya fumigata?
Designing efficient CRISPR-Cas9 experiments to study prm1 function in Neosartorya fumigata requires optimization at multiple levels:
Table 4. CRISPR-Cas9 Optimization for prm1 Modification in Neosartorya fumigata
| Component | Optimization Strategy | Critical Considerations |
|---|---|---|
| Guide RNA Design | Target conserved functional domains; minimize off-target effects | High GC content in Aspergillus genomes may affect gRNA efficiency |
| Delivery Method | Protoplast transformation; Agrobacterium-mediated transfer | Fungal cell walls require specialized transformation techniques |
| Cas9 Expression | Codon-optimization; appropriate promoter selection | gpdA or tef1 promoters typically show good expression in filamentous fungi |
| HDR Template | Homology arms of 500-1000 bp; include reporter genes | Longer homology arms increase recombination efficiency |
| Selection Strategy | Hygromycin B resistance; fluorescent markers | Positive-negative selection strategies enhance screening efficiency |
| Verification | PCR screening; sequencing; Western blotting; phenotypic assays | Multiple verification methods confirm precise editing |
For structure-function studies of prm1, consider:
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Domain-specific editing rather than complete gene knockout
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Introduction of point mutations in predicted functional residues
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Creation of chimeric proteins by domain swapping with homologs
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Integration of epitope tags for localization and interaction studies
Control experiments should include non-targeting gRNAs and complementation with wild-type prm1 to confirm phenotype specificity.
What high-throughput screening methods are most effective for identifying modulators of prm1 function?
High-throughput screening (HTS) for prm1 modulators requires specialized approaches due to its membrane-associated nature:
Table 5. High-Throughput Screening Methods for prm1 Modulators
| Screening Approach | Implementation | Advantages and Limitations |
|---|---|---|
| Cell-Based Assays | Split fluorescent protein complementation across fusing membranes | Directly measures fusion activity; may have high background |
| FRET-based assays using labeled membrane components | Good signal-to-noise ratio; requires specialized equipment | |
| Content mixing assays with self-quenching fluorophores | Quantitative readout; technically challenging setup | |
| Biochemical Assays | Liposome fusion assays with reconstituted prm1 | Direct measurement of function; requires purified protein |
| Surface plasmon resonance for binding studies | Detects direct interactions; high sensitivity | |
| Thermal shift assays to identify stabilizing compounds | Simple implementation; indirect measure of binding | |
| Computational Methods | Virtual screening against prm1 structural models | Cost-effective initial screening; depends on model accuracy |
| Molecular dynamics simulations to identify binding sites | Provides mechanistic insight; computationally intensive |
A tiered screening strategy is recommended:
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Begin with higher-throughput, lower-specificity primary screens
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Confirm hits with secondary assays that more directly measure prm1 function
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Validate promising candidates with orthogonal assays that rule out false positives
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Assess structure-activity relationships to optimize lead compounds
Counter-screens should be incorporated to identify compounds with general membrane effects rather than specific prm1 activity.
How might understanding prm1 function in Neosartorya fumigata contribute to antifungal drug development?
The study of prm1 in Neosartorya fumigata offers several promising avenues for antifungal drug development:
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Novel target identification: Membrane fusion proteins represent an underexplored class of antifungal targets. As A. fumigatus is one of the most common mold infections worldwide with increasing drug resistance, new targets are urgently needed .
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Mechanistic insights: The fundamental role of prm1 in membrane fusion processes makes it potentially essential for fungal growth, reproduction, and pathogenicity. Drugs targeting these essential processes could have broad antifungal activity.
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Selective targeting: Species-specific differences in prm1 could enable selective targeting of pathogenic fungi while sparing beneficial microorganisms, potentially reducing side effects.
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Resistance management: As a novel target, prm1 would not be affected by existing resistance mechanisms. The essential nature of membrane fusion for fungal viability might also reduce the likelihood of resistance development.
The increasing prevalence of invasive aspergillosis in immunocompromised patients and the limited arsenal of effective antifungals highlight the need for new therapeutic approaches . Membrane proteins like prm1 represent promising alternatives to traditional targets such as ergosterol synthesis and cell wall components.
What transcriptomic and proteomic approaches can provide insights into prm1 regulation in Neosartorya fumigata?
Integrating transcriptomic and proteomic approaches can reveal comprehensive insights into prm1 regulation:
Table 6. Multi-Omics Approaches for Studying prm1 Regulation
| Approach | Methodology | Insights Provided |
|---|---|---|
| Transcriptomic Methods | ||
| RNA-seq | Next-generation sequencing of mRNA | Identifies conditions inducing prm1 expression; reveals co-regulated genes |
| ChIP-seq | Chromatin immunoprecipitation followed by sequencing | Maps transcription factors binding to prm1 promoter |
| CAGE | Cap analysis gene expression | Precisely maps transcription start sites; identifies alternative promoters |
| Proteomic Methods | ||
| Global Proteomics | Mass spectrometry-based protein identification | Quantifies prm1 protein levels across conditions |
| Phosphoproteomics | Enrichment and analysis of phosphorylated peptides | Identifies regulatory post-translational modifications |
| Interaction Proteomics | Co-immunoprecipitation; proximity labeling | Maps prm1 protein-protein interaction network |
| Integrated Approaches | ||
| Multi-omics Integration | Correlation analysis of transcriptomic and proteomic data | Reveals post-transcriptional regulation mechanisms |
| Network Analysis | Computational integration of multiple datasets | Positions prm1 within cellular pathways |
Experimental designs should include:
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Multiple environmental conditions relevant to the fungal lifecycle
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Comparison of wild-type to prm1 mutant strains
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Time-course analyses to capture dynamic regulation
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Host-pathogen interaction models to assess regulation during infection
These approaches can elucidate the regulatory networks controlling prm1 expression and identify proteins that interact with prm1, providing a systems-level understanding of its function.
What contradictions exist in current research on fungal membrane fusion proteins and how might they be resolved?
Current research on fungal membrane fusion proteins like prm1 presents several unresolved contradictions:
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Functional conservation vs. sequence divergence:
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Despite significant sequence divergence across fungal species, membrane fusion proteins often maintain similar functions
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This contradiction can be resolved through structural biology approaches that identify conserved three-dimensional features despite sequence differences
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Variable phenotypic impacts of prm1 deletion:
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The severity of prm1 deletion phenotypes varies across species and experimental conditions
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Systematic investigation of genetic backgrounds and environmental conditions can help explain these discrepancies
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Mechanistic uncertainties:
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Whether prm1 acts directly in membrane merger or as a regulatory factor remains debated
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Reconstitution experiments with purified components can distinguish between direct and indirect roles
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Regulatory pathway discrepancies:
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Different studies report varying regulatory pathways controlling prm1 expression
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Comprehensive transcriptomic analysis across multiple conditions and species can identify core conserved regulatory elements
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To resolve these contradictions, researchers should:
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Employ standardized experimental conditions and strains
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Develop quantitative assays that permit precise measurement of membrane fusion activity
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Utilize structural biology approaches to understand functional domains
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Conduct comparative studies across multiple fungal species
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Integrate in vitro biochemical studies with in vivo functional analyses
By systematically addressing these contradictions, researchers can develop a unified model of prm1 function that accommodates the diverse experimental observations reported in the literature.
