Recombinant Saccharomyces cerevisiae Uncharacterized Protein YDR119W-A (YDR119W-A), also designated as Cox26, is a mitochondrial protein encoded by the YDR119W-A gene in S. cerevisiae. Initially annotated as uncharacterized, recent studies have reclassified it as a stoichiometric subunit of the III–IV supercomplex (a multi-enzyme assembly of complexes III and IV in the mitochondrial respiratory chain) .
Cox26 (YDR119W-A) is exclusively associated with the III–IV supercomplex, interacting directly with Cox2 (a core subunit of complex IV) . Key findings:
Supercomplex Stabilization: Deletion of YDR119W-A (Δcox26) disrupts III–IV supercomplex integrity, reducing complex IV activity .
Localization: Co-localizes with respirasomes via interaction with complex IV subunits .
Pathway Involvement: Linked to mitochondrial cristae morphology and respiratory chain efficiency .
Cox26’s role was elucidated through proteomic and genetic studies:
Proteomic Identification: Initially detected via mass spectrometry in III–IV supercomplex preparations .
Gene Deletion Analysis: Δcox26 mutants showed impaired supercomplex formation and reduced mitochondrial respiration .
Evolutionary Conservation: Homologs identified in other yeast species, though functional data remain limited .
KEGG: sce:YDR119W-A
STRING: 4932.YDR119W-A
S. cerevisiae is an excellent model organism for studying uncharacterized proteins due to several key advantages. It is inherently nonpathogenic, can be easily engineered to express proteins in large quantities, and can be rapidly propagated and purified . Furthermore, approximately 30% of genes implicated in human disease may have orthologs in the yeast proteome, making it valuable for studying protein functions with potential human relevance . For uncharacterized proteins like YDR119W-A, yeast offers well-established genetic manipulation tools, a fully sequenced genome, and extensive databases of protein interactions that facilitate functional characterization through comparative genomics and proteomic approaches .
Initial characterization typically follows a systematic approach:
Bioinformatic analysis: Sequence alignment with orthologs across species to predict functional domains and evolutionary conservation .
Expression profiling: Determining when and where the protein is expressed using RNA-seq and proteomics approaches.
Protein localization: Using GFP tagging to determine subcellular localization.
Interaction studies: Employing yeast two-hybrid or co-immunoprecipitation to identify protein-protein interactions.
Phenotypic analysis: Creating knockout strains and assessing phenotypic changes under various conditions.
This multifaceted approach provides complementary data points that collectively suggest potential functions for previously uncharacterized proteins .
For recombinant expression of yeast proteins like YDR119W-A, several systems can be considered, each with specific advantages:
Yeast-based expression systems:
Constitutive promoters: The TEF2 (translation elongation factor 1-alpha) promoter provides high-level constitutive expression, similar to what has been used for other recombinant proteins in S. cerevisiae .
Inducible systems: Copper-inducible promoters allow controlled expression timing, though for some applications, constitutive promoters may be preferred .
Expression vectors:
High-copy 2μM expression plasmids (such as pGI-100) serve as effective backbone vectors for recombinant protein expression .
When expressing YDR119W-A, researchers should consider codon optimization, inclusion of appropriate tags for detection and purification, and verification of expression using immunoblot analysis with specific antibodies, similar to methods described for other recombinant proteins in S. cerevisiae .
For optimal PCR amplification of YDR119W-A from S. cerevisiae genomic DNA, the following methodological approach is recommended:
Primer design: Design gene-specific primers that incorporate restriction sites compatible with your expression vector. For example:
Forward primer: 5'-CGGAATTC(EcoRI site)-(20-25 bp of gene-specific sequence)-3'
Reverse primer: 5'-ATAAGAATGCGGCCGC(NotI site)-(20-25 bp of gene-specific sequence)-3'
PCR reaction components:
High-fidelity DNA polymerase (e.g., Phusion or Q5)
Buffer system optimized for GC-rich yeast genomic DNA
DMSO (2-5%) to reduce secondary structure formation
Template: 50-100 ng of genomic DNA
Thermal cycling conditions:
Initial denaturation: 98°C for 3 minutes
30-35 cycles of:
Denaturation: 98°C for 15 seconds
Annealing: 55-65°C for 20 seconds (optimize based on primer Tm)
Extension: 72°C for 30 seconds per kb
Final extension: 72°C for 5 minutes
This approach parallels methods used for amplifying other yeast genes for recombinant expression, such as those described for CEA cDNA amplification in the reference .
Validation of recombinant YDR119W-A expression requires a comprehensive approach:
Molecular verification:
PCR confirmation of gene insertion in the expression vector
Sequencing to verify the absence of mutations
Protein expression analysis:
Immunoblot analysis using antibodies against an epitope tag (if included) or custom antibodies against YDR119W-A
Comparison with wild-type yeast to confirm overexpression
Quantitative assessment:
Densitometric analysis of Western blots
Mass spectrometry-based quantification
For effective immunoblotting, researchers should use appropriate controls and verify both the expected molecular weight and post-translational modifications of the protein, as seen in the example where a recombinant protein showed both 71 kDa and 130 kDa bands due to differential glycosylation and GPI anchoring .
Several complementary techniques are recommended for studying protein-protein interactions involving uncharacterized proteins like YDR119W-A:
Yeast two-hybrid (Y2H) screening:
Construct bait plasmids with YDR119W-A fused to a DNA-binding domain
Screen against a prey library of S. cerevisiae proteins
Validate positive interactions with secondary assays
Affinity purification coupled with mass spectrometry (AP-MS):
Express tagged YDR119W-A in yeast
Purify protein complexes using the tag
Identify interacting partners by mass spectrometry
Proximity-dependent biotin identification (BioID):
Fuse YDR119W-A with a biotin ligase
Identify proximal proteins through biotinylation
Purify and identify biotinylated proteins
Co-immunoprecipitation (Co-IP):
Use antibodies against YDR119W-A or a tag
Pull down protein complexes
Identify partners by Western blot or mass spectrometry
These methods should be applied in combination to build confidence in identified interactions, as each has specific strengths and limitations. The orthology-based approaches used to identify functional relationships in S. cerevisiae can help prioritize candidate interactors for validation .
Comparative genomic analysis for functional prediction of YDR119W-A should follow this methodological framework:
Ortholog identification:
Phylogenetic profiling:
Map the presence/absence pattern of YDR119W-A orthologs across species
Identify proteins with similar phylogenetic profiles, suggesting functional relationships
Domain architecture analysis:
Identify conserved domains and motifs
Compare domain organization across orthologs
Genomic context analysis:
Examine neighboring genes in various species (synteny)
Identify conserved gene clusters that might indicate functional relationships
Integration with high-throughput data:
Correlate comparative genomics predictions with expression data
Incorporate protein-protein interaction networks
This approach has successfully identified functions for previously uncharacterized yeast proteins and can help determine which organisms would be appropriate models for extrapolating YDR119W-A function .
For generating precise YDR119W-A knockout strains using CRISPR-Cas9, researchers should implement the following methodological approach:
gRNA design:
Select target sequences with minimal off-target effects
Design gRNAs targeting the coding region early in the sequence
Use yeast-optimized CRISPR-Cas9 systems
Repair template construction:
Design repair templates with 40-60 bp homology arms flanking the target site
Include selectable markers (e.g., antibiotic resistance genes)
Consider including unique restriction sites for screening
Transformation and selection protocol:
Co-transform gRNA plasmid, Cas9 expression plasmid, and repair template
Select transformants on appropriate media
Confirm knockouts by PCR, sequencing, and Western blotting
Phenotypic analysis workflow:
Compare growth rates under various conditions
Analyze cellular morphology and ultrastructure
Perform transcriptome and proteome analysis of knockout strains
This approach allows precise genome editing while minimizing off-target effects, providing a powerful tool for functional characterization of YDR119W-A.
Quantitative proteomics offers powerful approaches for studying YDR119W-A expression and regulation:
Sample preparation workflow:
Culture S. cerevisiae under various conditions
Extract proteins using optimized lysis buffers
Perform protein digestion (trypsin/Lys-C mix)
Labeling and fractionation strategies:
SILAC labeling for direct comparison of conditions
TMT or iTRAQ for multiplexed analysis
High-pH reversed-phase fractionation to increase proteome coverage
Mass spectrometry analysis:
Data-dependent acquisition for discovery
Parallel reaction monitoring for targeted quantification
Data-independent acquisition for comprehensive analysis
Data analysis pipeline:
Protein identification using database search algorithms
Quantification using appropriate software tools
Statistical analysis to identify significant changes
Post-translational modification analysis:
Phosphorylation site mapping
Glycosylation profiling
Ubiquitination analysis
These approaches allow researchers to track YDR119W-A abundance changes and identify regulatory mechanisms under different conditions, providing insights into its function and regulation.
RNA-seq data analysis for YDR119W-A expression should follow this structured methodological framework:
Experimental design considerations:
Include biological replicates (minimum 3)
Sample cells under relevant conditions (stress, developmental stages)
Consider time-course experiments to capture expression dynamics
Quality control measures:
Assess raw read quality (FastQC)
Filter low-quality reads
Remove adapter sequences
Alignment and quantification protocol:
Align reads to the S. cerevisiae reference genome
Quantify expression using count-based methods
Calculate FPKM/TPM values for normalization
Differential expression analysis:
Apply appropriate statistical methods (DESeq2, edgeR)
Control for false discovery rate
Validate key findings with qRT-PCR
Integration with other data types:
This systematic approach enables researchers to generate robust insights into YDR119W-A expression patterns and regulatory mechanisms across different conditions.
For robust statistical analysis of phenotypic data from YDR119W-A mutant strains, researchers should implement:
Experimental design optimization:
Power analysis to determine appropriate sample sizes
Inclusion of appropriate controls (wild-type, other relevant mutants)
Randomization and blinding where applicable
Descriptive statistics:
Inferential statistics:
Data presentation guidelines:
Advanced analysis approaches:
Multivariate analysis for complex phenotypes
Machine learning for pattern recognition
Network analysis to contextualize findings
This approach ensures statistical rigor and reproducibility in phenotypic analyses of YDR119W-A mutant strains.
For effective visualization of YDR119W-A protein structure predictions, researchers should follow these methodological guidelines:
Structure prediction workflow:
Generate multiple models using different algorithms (AlphaFold2, RoseTTAFold)
Evaluate model quality using established metrics (pLDDT, TM-score)
Refine models as needed
Visualization techniques:
Use specialized software (PyMOL, ChimeraX, VMD)
Apply appropriate rendering methods for different structural features
Create multiple views highlighting key domains and motifs
Comparative visualization strategies:
Superimpose models with known structures of related proteins
Create morph animations between conformational states
Generate electrostatic surface representations
Figure preparation for publication:
Include scale bars and orientation markers
Use consistent color schemes across related figures
Provide both cartoon and surface representations
Interactive visualization options:
Prepare interactive figures for online publications
Create 3D printable models for educational purposes
Develop AR/VR visualizations for complex structural relationships
This comprehensive approach ensures that structural predictions are effectively communicated, facilitating hypothesis generation about YDR119W-A function based on structural features.
For comprehensive identification of conditions affecting YDR119W-A function, researchers should implement:
Chemical genomics screening protocol:
Test YDR119W-A mutant strains against diverse chemical libraries
Employ concentration gradients to determine sensitivity/resistance profiles
Use automated growth monitoring systems for quantitative assessment
Environmental perturbation screening:
Systematically vary temperature, pH, osmolarity, and carbon sources
Monitor growth rates, morphology, and metabolic parameters
Employ microfluidic systems for precise environmental control
Genetic interaction screening:
Create double mutant collections using synthetic genetic array technology
Quantify genetic interactions (synthetic lethality, epistasis)
Construct interaction networks to position YDR119W-A in cellular pathways
Monitoring approach optimization:
Employ fluorescent reporters for real-time phenotypic readouts
Use high-content imaging for morphological analysis
Implement metabolomic profiling for biochemical phenotypes
Data analysis and interpretation framework:
This systematic approach allows researchers to comprehensively map conditions affecting YDR119W-A function, providing insights into its cellular roles and regulatory mechanisms.
To systematically determine YDR119W-A interactions with specific cellular pathways, researchers should implement:
Pathway-focused genetic interaction analysis:
Generate double mutants with key pathway components
Quantify genetic interactions using growth-based assays
Calculate interaction scores to identify suppressors/enhancers
Biochemical pathway analysis:
Measure pathway output in YDR119W-A mutants
Monitor metabolite levels using targeted metabolomics
Assess flux through pathways using isotope labeling
Pathway reporter assays:
Construct fluorescent/luminescent reporters for pathway activity
Compare reporter signals in wild-type and YDR119W-A mutants
Perform time-course analysis during pathway activation
Phosphoproteomic analysis:
Quantify pathway-specific phosphorylation events
Compare phosphorylation patterns between wild-type and mutants
Identify altered signaling nodes
Computational pathway modeling:
Integrate experimental data into pathway models
Simulate pathway behavior with and without YDR119W-A
Test predictions with targeted experiments
This multifaceted approach allows researchers to comprehensively map YDR119W-A's involvement in cellular pathways, similar to how other yeast proteins have been functionally characterized through pathway analysis .
To systematically identify and characterize potential human orthologs of YDR119W-A with disease relevance, researchers should implement:
Ortholog identification workflow:
Functional conservation assessment:
Test human candidate genes for complementation in yeast YDR119W-A mutants
Compare protein interaction networks between species
Assess conservation of post-translational modifications
Disease association analysis:
Search disease mutation databases for variants in candidate orthologs
Analyze GWAS data for disease associations
Examine expression patterns in disease-relevant tissues
Experimental validation approaches:
Create equivalent mutations in yeast and human cell models
Compare phenotypes across species
Assess conservation of protein localization and interactions
Translational potential evaluation:
This comprehensive approach leverages the finding that approximately 30% of genes implicated in human disease have orthologs in the yeast proteome , making it a valuable model organism for studying conserved disease mechanisms.
Methodological Approach | Technical Complexity | Required Resources | Time Investment | Information Yield | Best For |
---|---|---|---|---|---|
Bioinformatic Analysis | Low-Medium | Computational resources | 1-2 weeks | Initial functional predictions | First-pass characterization |
Gene Knockout (CRISPR) | Medium | Molecular biology laboratory | 3-4 weeks | Loss-of-function phenotypes | Essential function determination |
RNA-seq | Medium-High | Sequencing platform | 4-6 weeks | Expression patterns | Regulatory mechanisms |
Protein-Protein Interactions | High | Mass spectrometry, Y2H system | 2-3 months | Interaction networks | Pathway positioning |
Recombinant Expression | Medium | Molecular biology laboratory | 4-6 weeks | Protein characteristics | Biochemical function |
Localization Studies | Medium | Fluorescence microscopy | 3-4 weeks | Subcellular distribution | Compartment-specific roles |
Comparative Genomics | Medium | Computational resources | 2-3 weeks | Evolutionary conservation | Cross-species relevance |
Chemical Genomics | High | Robotics, compound libraries | 3-4 months | Condition-specific functions | Drug-target discovery |
Several high-potential research directions for YDR119W-A characterization include:
Integrative multi-omics approaches combining transcriptomics, proteomics, and metabolomics to comprehensively map YDR119W-A's functional impact across cellular systems.
Evolutionary functional genomics to trace the protein's functional conservation across species, potentially revealing fundamental biological roles preserved through evolution .
Systems biology modeling to position YDR119W-A within the broader cellular network context, predicting its importance in maintaining cellular homeostasis under various conditions.
Human disease modeling using YDR119W-A as a platform to understand orthologous human proteins potentially implicated in disease, leveraging the finding that approximately 30% of disease-associated human genes have yeast orthologs .
Synthetic biology applications exploring the potential utility of YDR119W-A in engineered biological systems, potentially building on S. cerevisiae's established role as a chassis for recombinant protein production .
These directions collectively represent a comprehensive strategy to fully elucidate the biological significance of this uncharacterized protein, moving from basic characterization to potential translational applications.
When reporting inconclusive or contradictory findings about YDR119W-A, researchers should follow these methodological guidelines:
Transparent data presentation:
Methodological transparency:
Detail all experimental conditions and variables
Acknowledge limitations of techniques used
Provide complete methodological details to enable replication
Context-appropriate interpretation:
Future research recommendations:
Suggest alternative approaches to resolve contradictions
Propose experiments that could clarify inconclusive results
Outline hypothesis-driven research to address uncertainties
This approach ensures scientific integrity while advancing the collective understanding of YDR119W-A, even when initial findings are unclear or seemingly contradictory.
Comprehensive benchmarks for evaluating successful YDR119W-A characterization include:
Functional assignment confidence metrics:
Multiple lines of evidence supporting functional predictions
Statistical confidence measures for predicted functions
Experimental validation of key predictions
Comparative characterization standards:
Interaction network quality assessment:
Confidence scores for protein-protein interactions
Validation through multiple orthogonal methods
Integration with existing interaction networks
Phenotypic characterization completeness:
Integration with existing knowledge:
Consistency with known pathway components
Resolution of contradictions with existing literature
Contribution to broader understanding of cellular processes