Recombinant Struthio camelus NADH-ubiquinone oxidoreductase chain 3 (MT-ND3)
Description
Overview of NADH-ubiquinone oxidoreductase (Complex I)
NADH-ubiquinone oxidoreductase, commonly known as Complex I, represents the largest and most intricate enzyme complex in the mitochondrial respiratory chain. This multisubunit protein complex serves as the primary entry point for electrons into the respiratory chain, playing a pivotal role in cellular energy production. Complex I catalyzes the transfer of electrons from NADH to ubiquinone, coupled with the translocation of protons across the inner mitochondrial membrane, contributing to the electrochemical gradient that drives ATP synthesis .
Role of ND3 in the Respiratory Chain
The ND3 protein constitutes one of the core subunits of Complex I that belongs to the minimal assembly required for catalysis. Its primary function involves the transfer of electrons from NADH to the respiratory chain, with ubiquinone serving as the immediate electron acceptor for the enzyme . Based on homologous proteins, MT-ND3 likely plays a crucial role in the proton-translocating mechanism of Complex I, contributing significantly to the generation of the proton gradient across the inner mitochondrial membrane.
This proton gradient subsequently drives ATP synthesis through oxidative phosphorylation, highlighting the fundamental importance of ND3 in cellular energy metabolism. The specific role of Struthio camelus MT-ND3 would be expected to align with these general functions, potentially with adaptations specific to avian metabolism.
Mitochondrial Origin and Genetic Context
The MT-ND3 gene is encoded by the mitochondrial genome, reflecting the endosymbiotic origin of mitochondria. In birds like the common ostrich, the mitochondrial DNA (mtDNA) exists as a circular, double-stranded molecule that encodes a limited set of proteins, primarily components of the respiratory chain complexes . The mitochondrial localization of the ND3 gene underscores its evolutionary conservation and essential role in oxidative phosphorylation.
In Struthio camelus, the MT-ND3 gene would be part of the mitochondrial genome, subject to maternal inheritance patterns typical of mitochondrial genes. The genetic context and organization of the MT-ND3 gene within the ostrich mitochondrial genome provide insights into the evolutionary history and functional constraints of this essential respiratory protein.
Taxonomic Classification of Struthio camelus
The common ostrich (Struthio camelus) represents the largest living bird species and belongs to the order Struthioniformes and family Struthionidae. As a flightless bird, the ostrich has evolved distinctive physiological adaptations, including a unique respiratory system and metabolic capabilities that support its remarkable running speed and endurance . The evolutionary position of ratites, including ostriches, within the avian phylogeny provides an important context for studying mitochondrial proteins like MT-ND3.
Ostriches are native to Africa and are characterized by their large size, long necks, and powerful legs. The species has been noted for laying the largest eggs of any living bird, reflecting its distinctive reproductive strategy . The evolutionary history of ostriches provides a fascinating context for studying their mitochondrial proteins and understanding potential adaptations in energy metabolism.
Genome Assembly and Mitochondrial DNA
The genome of Struthio camelus has been the subject of advanced sequencing and assembly efforts. Chromosome-length genome assembly for the common ostrich has been performed using 3D-DNA pipeline and reviewed using Juicebox Assembly Tools, providing valuable genomic data for this species . The mitochondrial genome, containing the MT-ND3 gene, would be expected to follow the typical organization of avian mitochondrial DNA.
Hi-C technology has been employed in the genomic analysis of the ostrich, allowing for the generation of contact maps and visualization of genomic alignments . These advanced genomic techniques provide a foundation for understanding the genetic context of mitochondrial genes like MT-ND3 and their evolutionary relationships with homologous genes in other species.
Comparative Mitochondrial Genomics
Comparative analysis of mitochondrial genomes across avian species reveals patterns of conservation and divergence that reflect functional constraints and evolutionary adaptations. The MT-ND3 gene of Struthio camelus would be expected to show significant sequence similarity with homologous genes in other birds, particularly ratites, while also potentially exhibiting unique features related to the ostrich's distinctive physiology and evolutionary history.
The comparative analysis of avian MT-ND3 sequences can provide insights into the selective pressures acting on this gene and its protein product, potentially revealing adaptations associated with the evolution of flightlessness or other aspects of ostrich biology. These comparative studies contribute to our understanding of mitochondrial evolution in birds and the functional significance of individual subunits like MT-ND3 in Complex I.
Protein Structure and Sequence Features
The MT-ND3 protein from Struthio camelus would be expected to share structural features with homologous proteins from other species, including multiple transmembrane domains that anchor the protein within the inner mitochondrial membrane. Based on related proteins like the NADH-ubiquinone oxidoreductase chain 3 from Yarrowia lipolytica, the ostrich MT-ND3 likely consists of hydrophobic regions forming membrane-spanning alpha-helices interspersed with more hydrophilic loops .
These structural elements would contribute to the protein's function within Complex I, potentially participating in proton translocation across the membrane and interactions with other subunits of the complex. The specific sequence features of ostrich MT-ND3 would reflect both the evolutionary conservation of functionally critical regions and potential adaptations specific to avian metabolism.
Functional Domains and Conserved Motifs
Struthio camelus MT-ND3 would be expected to contain functional domains classified as "NADH-ubiquinone/plastoquinone oxidoreductase, chain 3" based on homology with related proteins . These domains are critical for the protein's role in electron transport and proton translocation within Complex I. Conserved motifs within these domains likely include residues involved in interactions with other Complex I subunits, ubiquinone binding, and the mechanism of proton pumping.
The specific arrangement of these domains and motifs in ostrich MT-ND3 would reflect the protein's functional requirements within the context of avian mitochondrial respiration. Comparative analysis of these domains across species can provide insights into the evolution of Complex I function and the specific adaptations that may have occurred in the ostrich lineage.
Post-translational Modifications and Regulation
Post-translational modifications (PTMs) likely play important roles in regulating the function, stability, and interactions of Struthio camelus MT-ND3 within Complex I. While specific information on PTMs of ostrich MT-ND3 is not provided in the available data, common modifications of mitochondrial proteins include phosphorylation, acetylation, and other covalent modifications that can influence protein activity and interactions.
These modifications could regulate MT-ND3 function in response to cellular energy demands, oxidative stress, or other physiological signals. The study of PTMs in recombinant MT-ND3 proteins provides opportunities to investigate the regulatory mechanisms that control mitochondrial function in the ostrich and other species.
Expression Systems Overview
Recombinant production of Struthio camelus MT-ND3 involves the use of various expression systems to generate the protein for research and analytical purposes. Commercial sources like CUSABIO offer recombinant ostrich MT-ND3 produced in different expression hosts, including yeast, E. coli, baculovirus, and mammalian cells . Each expression system provides distinct advantages and challenges, influencing the yield, folding, and post-translational modifications of the recombinant protein.
The availability of recombinant ostrich MT-ND3 from multiple expression platforms facilitates a range of structural, functional, and comparative studies of this important mitochondrial protein. Researchers can select the expression system that best aligns with their specific experimental requirements and constraints.
Bacterial Expression Systems
Bacterial expression, particularly in E. coli, represents a commonly used system for producing recombinant proteins. CUSABIO offers E. coli-expressed recombinant Struthio camelus MT-ND3 (product code CSB-EP015078FOU1), as well as a biotinylated version using AviTag-BirA technology (CSB-EP015078FOU1-B) . The biotinylated variant features specific attachment of biotin to an AviTag peptide, enhancing detection and immobilization capabilities for specialized applications.
Yeast Expression Systems
Yeast expression systems provide a eukaryotic cellular environment that can facilitate proper folding and some post-translational modifications of proteins like MT-ND3. CUSABIO offers yeast-expressed recombinant Struthio camelus MT-ND3 (product code CSB-YP015078FOU1) . The yeast system may be particularly suitable for producing functional MT-ND3 protein, given the presence of mitochondria in yeast cells and the more compatible cellular machinery for eukaryotic protein processing.
This expression platform represents a middle ground between bacterial and higher eukaryotic systems, offering improved protein folding while maintaining reasonable yields and costs. The recombinant ostrich MT-ND3 produced in yeast may better reflect the native protein's characteristics in terms of folding and certain modifications.
Higher Eukaryotic Expression Systems
For applications requiring more authentic post-translational modifications and folding, baculovirus and mammalian expression systems offer significant advantages. CUSABIO provides recombinant Struthio camelus MT-ND3 produced in both baculovirus (CSB-BP015078FOU1) and mammalian cell (CSB-MP015078FOU1) systems . These higher eukaryotic platforms can generate recombinant protein with characteristics closely resembling the native protein, including proper folding, membrane insertion, and complex post-translational modifications.
While these systems typically yield lower protein quantities and have higher production costs compared to bacterial or yeast expression, they offer significant benefits for functional and structural studies requiring authentic protein characteristics. The choice between baculovirus and mammalian expression depends on specific research requirements and the particular aspects of protein biology being investigated.
Comparative Analysis of Expression Systems
The following table provides a comprehensive comparison of the different expression platforms available for recombinant Struthio camelus MT-ND3 production:
| Expression System | Product Code | Advantages | Limitations | Optimal Applications |
|---|---|---|---|---|
| E. coli | CSB-EP015078FOU1 | High yield, Low cost, Rapid production, Ease of genetic manipulation | Limited post-translational modifications, Potential folding issues for membrane proteins | Antigen production, Antibody generation, Basic structural studies |
| E. coli (Biotinylated) | CSB-EP015078FOU1-B | Specific biotinylation via AviTag, Enhanced detection and immobilization capabilities | Same limitations as standard E. coli expression | Protein interaction studies, Pull-down assays, Immobilization applications |
| Yeast | CSB-YP015078FOU1 | Eukaryotic expression environment, Better folding for membrane proteins, Some post-translational modifications | Moderate yield, Higher cost than bacterial systems | Functional studies, Certain structural analyses, Screening applications |
| Baculovirus | CSB-BP015078FOU1 | Near-native folding and modifications, Suitable for complex proteins | Lower yield, Higher cost, Longer production time | Functional assays, Structural biology, Interaction studies requiring authentic protein |
| Mammalian cell | CSB-MP015078FOU1 | Most authentic post-translational modifications, Native-like protein folding | Lowest yield, Highest cost, Most complex production process | High-fidelity functional studies, Detailed structural analyses, Therapeutic development |
This comparative analysis highlights the trade-offs between different expression systems, guiding researchers in selecting the appropriate platform based on their specific research requirements, budget constraints, and experimental goals .
Functional Studies and Biochemical Assays
Recombinant Struthio camelus MT-ND3 enables various functional studies and biochemical assays investigating the role of this protein in Complex I activity and mitochondrial function. These studies may include enzyme activity assays measuring electron transfer rates, proton translocation studies, and investigations of the protein's role in Complex I assembly and stability.
The availability of recombinant protein from different expression systems facilitates a range of functional analyses under various experimental conditions. Functional studies of ostrich MT-ND3 can provide insights into the unique bioenergetic properties of ratite birds, potentially revealing adaptations associated with their distinctive physiology and metabolic requirements.
Evolutionary and Comparative Studies
Evolutionary and comparative studies utilizing recombinant Struthio camelus MT-ND3 examine the conservation and divergence of this protein across species, providing insights into the evolutionary history of the respiratory chain. The analysis of MT-ND3 sequences from the ostrich and other birds can reveal patterns of selection pressure, adaptive evolution, and functional constraints on this essential mitochondrial protein.
Comparative studies between avian and mammalian MT-ND3 proteins, such as those from ostrich and platypus , can highlight shared features essential for function as well as lineage-specific adaptations. These evolutionary analyses contribute to a broader understanding of mitochondrial evolution and the specific adaptations that may have occurred in different vertebrate lineages.
Biomedical and Biotechnological Applications
The study of recombinant Struthio camelus MT-ND3 has potential biomedical and biotechnological applications extending beyond basic research. Complex I deficiencies, including mutations in ND3, are associated with various mitochondrial disorders in humans. Comparative studies of ND3 proteins from different species can provide insights into structure-function relationships relevant to understanding these disorders.
Additionally, the unique properties of avian MT-ND3 may offer novel perspectives for biotechnological applications, potentially including the development of bioenergetic sensors, mitochondrial targeting strategies, or biomimetic approaches inspired by the adaptations observed in ostrich mitochondrial proteins. The recombinant production of ostrich MT-ND3 provides a valuable resource for exploring these potential applications.
Product Specs
Note: While we prioritize shipping the format currently in stock, we are happy to accommodate specific format requests. Please indicate your preference in the order notes and we will do our best to fulfill your requirement.
Note: All proteins are shipped with standard blue ice packs. Should you require dry ice shipping, please inform us in advance. Additional fees may apply.
Generally, liquid form has a shelf life of 6 months at -20°C/-80°C. Lyophilized form typically has a shelf life of 12 months at -20°C/-80°C.
Target Background
Q&A
What is MT-ND3 and what is its functional significance in mitochondrial biology?
MT-ND3 encodes the NADH-ubiquinone oxidoreductase chain 3, which functions as a core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I). This protein is believed to be part of the minimal assembly required for catalysis within Complex I, which is crucial for transferring electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone .
In comparative studies, MT-ND3 has been identified as an essential component for proper assembly and function of Complex I across species. Its conservation underscores its critical role in mitochondrial energy production through oxidative phosphorylation (OXPHOS).
How does Struthio camelus MT-ND3 differ structurally from human MT-ND3?
While specific structural comparisons between Struthio camelus (common ostrich) MT-ND3 and human MT-ND3 are not fully characterized in the current literature, analysis techniques similar to those used for MT-ND4 can be applied. Recombinant proteins from various species, including avian sources like Struthio camelus, are typically studied using expression systems such as baculovirus vectors, which have been successfully employed for MT-ND4 .
Sequence alignment analysis using programs like Clustal W would be the first step in comparing the amino acid sequences and identifying conserved domains between human and ostrich MT-ND3, similar to approaches used for other mitochondrial proteins .
What expression systems are most effective for recombinant MT-ND3 production?
Multiple expression systems can be employed for MT-ND3 production, with selection depending on research requirements:
| Expression System | Advantages | Limitations |
|---|---|---|
| Baculovirus | High yield for complex proteins; post-translational modifications; suitable for membrane proteins | More complex setup; longer production time |
| E. coli | Rapid expression; cost-effective; well-established protocols | Limited post-translational modifications; may form inclusion bodies |
| Yeast | Eukaryotic post-translational modifications; high yield | Longer production time than bacterial systems |
| Mammalian cells | Native-like post-translational modifications; proper folding | Lower yields; higher cost; more complex maintenance |
For mitochondrial membrane proteins like MT-ND3, baculovirus expression systems are often preferred as they provide a eukaryotic environment suitable for proper folding and post-translational modifications . This approach has been successfully used for producing other Complex I components.
What purification strategies yield the highest purity of recombinant MT-ND3?
Purification of recombinant MT-ND3 requires careful consideration of its hydrophobic nature as a membrane protein. Based on protocols for similar proteins:
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Initial extraction with mild detergents such as Triton X-100 or DM (n-dodecyl-β-D-maltoside)
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Affinity chromatography utilizing fusion tags determined during the manufacturing process
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Size exclusion chromatography to separate the target protein from aggregates
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Ion exchange chromatography for additional purification if needed
Purity assessment via SDS-PAGE should aim for >85% purity, consistent with commercial recombinant protein standards . When working with mitochondrial membrane proteins, it's crucial to maintain the protein in appropriate detergent micelles throughout the purification process to prevent aggregation and preserve activity.
How can researchers effectively measure MT-ND3 activity in vitro?
In vitro activity measurement of MT-ND3 should be conducted within the context of Complex I activity, as MT-ND3 functions as part of this larger complex. Methodological approaches include:
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Spectrophotometric assays measuring NADH oxidation (340 nm, ε = 6.2 mM⁻¹cm⁻¹)
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Ubiquinone reduction assays using various ubiquinone analogues (UQ₁, UQ₂, UQ₆)
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Oxygen consumption measurements using oxygen electrodes
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Proton pumping assays using pH-sensitive probes
The reaction medium typically contains buffer (e.g., 50 mM NaPi buffer, pH 6.0), EDTA (1 mM), and appropriate protein concentration (approximately 0.066 μg/mL). Reactions can be initiated by adding NADH (100 μM) after equilibrating the enzyme with the substrate .
What methodologies are recommended for studying MT-ND3 mutations and their effects?
To study MT-ND3 mutations and their functional consequences:
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Site-directed mutagenesis to introduce specific mutations of interest
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Expression of wild-type and mutant proteins in appropriate cell models
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Comparative enzymatic activity assays between wild-type and mutant proteins
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Blue Native PAGE to assess Complex I assembly
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Cellular respiration measurements
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ROS production assays to determine if mutations affect electron leakage
Recent research has demonstrated that MT variants, such as 10398A>G, can function as expression quantitative trait loci (eQTL) for MT-ND3, affecting its expression levels . This approach can be adapted to study specific mutations in Struthio camelus MT-ND3 and compare them with human counterparts.
How does MT-ND3 contribute to mitochondrial heteroplasmy and what are the implications for neurodegenerative diseases?
MT-ND3 variants have been implicated in mitochondrial heteroplasmy (the presence of multiple mitochondrial DNA variants within a single cell), which has potential implications for neurodegenerative diseases. Research methodologies to investigate this relationship include:
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Next-generation sequencing to quantify heteroplasmy levels
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Tissue-specific analysis of MT-ND3 variants (brain vs. blood samples)
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Correlation analysis between MT-ND3 variants and heteroplasmy levels
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Gene network modeling to identify interactions with nuclear genes
For research focused on neurodegenerative diseases, it's important to note that while MT heteroplasmy was present throughout the entire MT genome in blood samples, it was primarily detected within the MT control region for brain samples . This tissue-specific difference must be considered when designing experimental protocols.
What approaches can be used to identify and characterize the ubiquinone binding site in relation to MT-ND3?
Characterizing the ubiquinone binding site in relation to MT-ND3 requires specialized techniques:
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Photoaffinity labeling using photoreactive biotinylated ubiquinone mimics
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Mass spectrometry analysis of cross-linked peptides
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Site-directed mutagenesis of predicted binding residues
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Computational modeling based on homologous structures
For photoaffinity labeling, researchers have successfully used photoreactive azido-Qs with biotin at the terminal end of the side chain, following the concept of minimal modification to maintain biological activity . This approach involves:
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Synthesis of appropriate azido-Q probes
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Incubation with the target protein
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UV irradiation to activate the azido group for cross-linking
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Digestion with specific proteases (CNBr, V8 protease, lysylendopeptidase)
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Identification of labeled peptides using streptavidin affinity and mass spectrometry
This methodology has successfully identified ubiquinone binding regions in other respiratory enzymes and could be adapted for studying MT-ND3.
How can researchers investigate the interaction between MT-ND3 and MT-ND4 within Complex I assembly?
The interaction between MT-ND3 and MT-ND4 is critical for proper Complex I assembly and function. Research approaches include:
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Co-immunoprecipitation using specific antibodies against MT-ND3 and MT-ND4
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Blue Native PAGE combined with Western blotting to analyze Complex I assembly states
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FRET (Förster Resonance Energy Transfer) or PLA (Proximity Ligation Assay) to detect protein-protein interactions
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Cross-linking mass spectrometry to identify interaction interfaces
When working with recombinant proteins, researchers can utilize both MT-ND3 and MT-ND4 from Struthio camelus (with data available for MT-ND4 ) to conduct comparative studies of their interactions and assembly properties. This would provide valuable insights into species-specific differences in Complex I assembly and function.
What are the common challenges in working with recombinant MT-ND3 and how can they be addressed?
Working with recombinant mitochondrial membrane proteins presents several challenges:
Shelf life considerations are also important - liquid preparations typically maintain stability for 6 months at -20°C/-80°C, while lyophilized forms can be stable for up to 12 months .
How can researchers optimize storage conditions for maintaining MT-ND3 activity?
Based on recommendations for similar mitochondrial proteins:
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Add glycerol to a final concentration of 5-50% (typically 50%) for long-term storage
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Aliquot the protein solution to avoid repeated freeze-thaw cycles
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Store at -20°C/-80°C for extended shelf life
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For working stocks, store aliquots at 4°C for up to one week
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Perform activity assays before and after storage to monitor stability
Prior to use, it is recommended to briefly centrifuge vials to bring contents to the bottom before opening . When reconstituting lyophilized protein, use deionized sterile water to achieve a concentration of 0.1-1.0 mg/mL .
