Recombinant Salmo trutta NADH-ubiquinone oxidoreductase chain 3 (MT-ND3)
Description
Biological Context and Classification
NADH-ubiquinone oxidoreductase chain 3, commonly abbreviated as MT-ND3, is a mitochondrial protein encoded by the mitochondrial DNA (mtDNA) gene of the same name. In Salmo trutta, commonly known as brown trout, this protein functions as a crucial component of the mitochondrial respiratory chain complex I, which is the first and largest enzyme complex in the oxidative phosphorylation system. The "MT" prefix in its name indicates its mitochondrial origin, distinguishing it from nuclear-encoded proteins involved in similar processes .
MT-ND3 belongs to a family of proteins known as NADH dehydrogenases, which are responsible for the transfer of electrons from NADH to ubiquinone in the respiratory chain. This process is fundamental to cellular energy production, as it initiates the electron transport chain that ultimately leads to ATP synthesis. Due to its critical role in energy metabolism, MT-ND3 is highly conserved across various species, making it valuable for both evolutionary studies and medical research .
Historical Research Significance
The ability to produce recombinant forms of MT-ND3 has opened new avenues for research, allowing scientists to study this protein's structure and function in controlled laboratory settings. This has been particularly valuable for investigating the impact of specific genetic variations on protein function and developing strategies to address associated pathologies .
Primary Structure and Amino Acid Composition
The primary structure of Salmo trutta MT-ND3 consists of 116 amino acids, forming a relatively small but functionally significant protein. The complete amino acid sequence is as follows:
MNLITTIIAITITLSAVLATVSFWLPQITPDAEKLSPYECGFDPLGSARLPFSLRFFLIAI LFLLFDLEIALLLPLPWGDQLATPALTLAWSAAVLALLTLGLIYEWTQGGLEWAE
This sequence is characterized by a high proportion of hydrophobic amino acids, reflecting the protein's function as a membrane-embedded component of the respiratory chain complex I. The specific arrangement of these amino acids contributes to the protein's ability to function within the lipid bilayer of the inner mitochondrial membrane, where it participates in electron transport .
Secondary and Tertiary Structure
While the exact three-dimensional structure of Salmo trutta MT-ND3 has not been fully elucidated, insights from homologous proteins suggest that it adopts a primarily α-helical conformation, with transmembrane domains spanning the inner mitochondrial membrane. These structural features are critical for the protein's role in the assembly and function of complex I, facilitating the proper alignment of electron transfer components within the respiratory chain .
The protein's structure is further characterized by specific domains that interact with other subunits of complex I, ensuring the proper assembly of this larger enzymatic complex. Disruptions to these interactions, such as those caused by genetic variants, can lead to impaired complex I assembly and function, resulting in reduced ATP production and associated pathological conditions .
Expression Systems and Methodology
Recombinant Salmo trutta MT-ND3 is typically produced using bacterial expression systems, with Escherichia coli being the most common host organism. The recombinant protein is often engineered to include additional features that facilitate its purification and subsequent applications, such as an N-terminal His tag .
The production process involves cloning the MT-ND3 gene into an appropriate expression vector, transforming the host bacteria, inducing protein expression, and subsequently purifying the target protein from the bacterial lysate. This approach allows for the controlled production of large quantities of the protein for various research applications .
Product Characteristics and Quality Control
The commercially available recombinant Salmo trutta MT-ND3, as described in the literature, exhibits the following characteristics:
| Parameter | Specification |
|---|---|
| Species | Salmo trutta (Brown trout) |
| Source | E. coli |
| Tag | His |
| Protein Length | Full Length (1-116) |
| Form | Lyophilized powder |
| Purity | Greater than 90% as determined by SDS-PAGE |
| Applications | SDS-PAGE |
| Storage Recommendations | Store at -20°C/-80°C upon receipt, aliquoting necessary for multiple use |
| Storage Buffer | Tris/PBS-based buffer, 6% Trehalose, pH 8.0 |
| Reconstitution | Recommended in deionized sterile water to 0.1-1.0 mg/mL with 5-50% glycerol |
Quality control for recombinant MT-ND3 typically involves SDS-PAGE analysis to confirm protein purity and integrity. Additional tests may include mass spectrometry to verify the protein's identity and structural integrity, ensuring that the recombinant product accurately represents the native protein's key features .
Role in Respiratory Chain Complex I
MT-ND3 serves as an integral component of respiratory chain complex I (NADH:ubiquinone oxidoreductase), the first and largest enzyme complex in the mitochondrial electron transport chain. This complex catalyzes the transfer of electrons from NADH to ubiquinone, coupled with the translocation of protons across the inner mitochondrial membrane. This process contributes to the establishment of a proton gradient that drives ATP synthesis, the primary energy currency of cells .
Within complex I, MT-ND3 appears to play a role in the assembly and stabilization of the complex, ensuring its proper function in electron transport. Research indicates that deficiencies in MT-ND3 can lead to impaired complex I assembly and reduced activity, resulting in decreased ATP production and associated cellular dysfunction .
Impact on ATP Production and Energy Metabolism
The functional integrity of MT-ND3 is critical for efficient ATP production through oxidative phosphorylation. Studies have demonstrated that variants in the MT-ND3 gene can significantly reduce protein levels, leading to complex I assembly deficiencies, reduced complex I activity, and consequently, diminished ATP synthesis .
This impact on energy metabolism has profound implications for cellular function, particularly in tissues with high energy demands such as the brain, heart, and skeletal muscle. The association between MT-ND3 variants and conditions like Leigh syndrome, a severe neurological disorder, underscores the protein's critical role in maintaining adequate energy supply for neuronal function and survival .
Genetic Variants and Their Functional Consequences
Several genetic variants in the MT-ND3 gene have been identified, with varying impacts on protein function and associated clinical manifestations. Notable variants include m.10197G > C and m.10191T > C, which have been documented in patients with mitochondrial disorders .
Functional analyses of the m.10197G > C variant, for example, have revealed significant reductions in MT-ND3 protein levels, leading to complex I assembly deficiencies, reduced complex I activity, and decreased ATP synthesis. These molecular consequences translate to clinical presentations characterized by energy deficiency and associated systemic manifestations .
Association with Mitochondrial Diseases
MT-ND3 variants are known to cause severe mitochondrial diseases, including Leigh syndrome and mitochondrial complex I deficiency. Leigh syndrome is a devastating neurological disorder characterized by progressive brain abnormalities, developmental delays, and movement disorders, ultimately leading to respiratory failure and early mortality in many cases .
The association between MT-ND3 variants and these conditions highlights the protein's critical role in maintaining mitochondrial function and cellular energy production. Understanding these relationships is essential for developing diagnostic approaches and therapeutic strategies for affected individuals .
Evolutionary Studies and Phylogenetic Relationships
MT-ND3, along with other mitochondrial genes, has proven valuable for studying evolutionary relationships and genetic diversity among Salmo trutta populations. Research has employed restriction fragment length polymorphism (RFLP) analysis of PCR-amplified mitochondrial DNA segments, including those encoding MT-ND3, to investigate genetic differentiation and phylogenetic relationships .
Studies have revealed significant genetic diversity among brown trout populations, with MT-ND3 and other mitochondrial genes showing distinct haplotypes that can be used to trace evolutionary lineages. For example, research on Greek Salmo trutta populations identified five phylogenetic assemblages based on mitochondrial DNA analysis, including segments encoding MT-ND3 .
Population Genetics and Conservation Biology
The genetic information derived from MT-ND3 analysis has important implications for conservation biology. Studies have demonstrated that many brown trout populations represent unique gene pools, possessing private mtDNA genotypes that warrant individual recognition for conservation and management purposes .
Research on Great Lakes brown trout, for instance, has utilized sequence analysis of mitochondrial regions, including ND-1 (closely related to ND-3), to determine strain assignments and European lineage origins. This information is valuable for understanding the genetic structure of introduced populations and informing conservation strategies .
Allotopic Expression Strategies
Recent research has explored innovative therapeutic approaches for addressing mitochondrial diseases associated with MT-ND3 variants. One promising strategy involves allotopic expression, which entails delivering mitochondrial genes into mitochondria through codon optimization for nuclear expression and translation by cytoplasmic ribosomes .
This approach has been adapted to rescue defects arising from MT-ND3 variants, with researchers constructing mitochondrial targeting sequences along with codon-optimized MT-ND3 for import into mitochondria. Studies have demonstrated that this technique can partially restore protein levels, alleviate complex I deficiency, and significantly improve ATP production in patients with m.10197G > C and m.10191T > C variants in MT-ND3 .
Future Therapeutic Prospects
The successful implementation of allotopic expression for rescuing MT-ND3 variant phenotypes represents a significant advancement in the field of mitochondrial medicine. This approach holds promise for addressing other mitochondrial diseases caused by mtDNA variants, potentially offering therapeutic options for conditions that currently have limited treatment modalities .
Future research may focus on optimizing these techniques to enhance their efficacy and safety, potentially leading to clinical applications for patients with mitochondrial diseases. Additionally, the development of recombinant MT-ND3 and related proteins may facilitate drug discovery efforts, enabling the identification of compounds that can modulate mitochondrial function and address energy deficiencies in affected tissues .
Product Specs
Note: We prioritize shipping the format currently in stock. However, if you have specific format requirements, please indicate them during order placement, and we will accommodate your request.
Note: All protein shipments are standardly packed with blue ice packs. If you require dry ice shipping, please notify us in advance. Additional fees may 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 the structure and function of Salmo trutta MT-ND3 protein?
The Salmo trutta (Brown trout) NADH-ubiquinone oxidoreductase chain 3 (MT-ND3) is a mitochondrially-encoded protein comprising 116 amino acids that functions as a component of Complex I (NADH:ubiquinone oxidoreductase) in the mitochondrial electron transport chain. The amino acid sequence is characterized by hydrophobic regions consistent with its role as a membrane-embedded subunit. MT-ND3 plays a critical role in proton translocation across the inner mitochondrial membrane, contributing to the establishment of the electrochemical gradient necessary for ATP synthesis . The protein's structural features include transmembrane domains that anchor it within the inner mitochondrial membrane, allowing it to participate in electron transfer and proton pumping activities essential for cellular respiration .
How is recombinant Salmo trutta MT-ND3 protein typically produced and purified for research applications?
Recombinant Salmo trutta MT-ND3 protein is commonly produced using E. coli expression systems, with the full-length protein (amino acids 1-116) fused to an N-terminal histidine tag to facilitate purification . The expression construct typically includes the complete MT-ND3 coding sequence optimized for prokaryotic expression. Following bacterial culture and protein expression induction, cells are harvested and lysed, and the recombinant protein is purified through nickel affinity chromatography, exploiting the interaction between the histidine tag and immobilized nickel ions. Subsequent purification steps may include size exclusion chromatography to achieve purity greater than 90% as determined by SDS-PAGE analysis . The purified protein is then typically lyophilized for long-term storage stability, with reconstitution recommended in deionized sterile water to a concentration of 0.1-1.0 mg/mL prior to experimental use .
What are the optimal storage and handling conditions for recombinant MT-ND3 protein?
For optimal stability and activity retention, recombinant MT-ND3 protein should be stored according to specific guidelines that minimize degradation and maintain functional integrity. Lyophilized MT-ND3 powder demonstrates superior stability, with a shelf life of approximately 12 months when stored at -20°C to -80°C . Upon reconstitution, the addition of glycerol to a final concentration of 5-50% (with 50% being standard practice) is recommended to prevent freeze-thaw damage during storage . Reconstituted protein solutions should be aliquoted to avoid repeated freeze-thaw cycles, which can significantly compromise protein structure and function. Working aliquots may be stored at 4°C for up to one week, while long-term storage requires -20°C or preferably -80°C conditions . Prior to use, vials should be briefly centrifuged to ensure all material collects at the bottom, particularly after thawing or initial reconstitution .
What methodological approaches are most effective for investigating MT-ND3 genetic variants and their functional impacts in aquatic species?
Investigating MT-ND3 genetic variants in aquatic species requires a multi-faceted approach combining genomic, proteomic, and functional analyses. High-throughput sequencing methodologies such as Illumina OmniExpressExome BeadArray provide comprehensive genotyping data, though specialized quality control procedures are essential for mitochondrial DNA analysis . Effective variant calling requires mapping to appropriate reference sequences (such as the revised Cambridge Reference Sequence for human studies) followed by rigorous filtering based on genotyping rate and contamination assessment using tools like HaploCheck . For functional impact assessment, integrating multiple computational prediction tools that evaluate sequence homology, evolutionary conservation, and protein structural information proves most effective. Specifically, combining scores from tools such as MutPred, mtDNA Selection, and MitoTool yields a robust functional impact (FI) score that correlates with pathogenicity potential . Additionally, haplogroup assignment using tools like HaploGrep 2 combined with principal component analysis facilitates population-level comparisons and evolutionary insights . For experimental validation of variant effects, site-directed mutagenesis of recombinant proteins followed by biochemical assays measuring electron transport efficiency and reactive oxygen species production provides direct functional evidence of variant impacts on respiratory complex assembly and activity.
How can researchers address the challenges of mitochondrial DNA recombination when studying MT-ND3 evolution in salmonid species?
Addressing mitochondrial DNA recombination challenges in MT-ND3 evolutionary studies requires a strategic approach that accounts for potential interspecific genetic exchange. Researchers should implement multiple recombination detection methods as demonstrated in studies of Hucho taimen, where seven distinct analytical approaches successfully identified recombination events within the MT-ND3 gene region . The program RDP3 has proven particularly effective for detecting such events with high statistical support (P values as low as 2.984×10^-25) . To overcome potential misinterpretations from recombination events, researchers should sequence extended mitochondrial regions (>8,000 bp) rather than relying on shorter fragments that might miss breakpoints between recombinant segments . Additionally, implementing a phylogenetic incongruence analysis across multiple mitochondrial genes can identify regions with discordant evolutionary signals indicative of recombination. For robust species identification, researchers should employ multiple nuclear markers alongside mitochondrial sequences to develop a concordance approach that can distinguish between shared ancestry and introgression events . When potential recombination is detected, determining the direction and timing of introgression requires analysis of both "major" and "minor" parental sequences and precise mapping of breakpoint positions, as illustrated in the analysis of introgression between Hucho taimen and Brachymystax subspecies .
What are the implications of MT-ND3 variants on mitochondrial function and their potential role in aging processes?
Recent evidence suggests that specific variants in MT-ND3, particularly m.10398A > G, may significantly impact mitochondrial function with downstream consequences for cellular aging processes . This non-synonymous mutation alters the protein structure of NADH-ubiquinone oxidoreductase chain 3, potentially affecting electron transport efficiency and reactive oxygen species (ROS) production . Functional impact analysis integrating multiple pathogenicity prediction tools has identified MT-ND3 variants that contribute to premature aging phenotypes even in young adults, suggesting these mutations may accelerate biological aging processes . Mechanistically, altered MT-ND3 function may disrupt OXPHOS Complex I assembly or activity, leading to compromised ATP production, increased oxidative stress, and subsequent mitochondrial and cellular damage that characterizes aging tissues . The novel functional impact (FI) scoring system developed for mtDNA variants offers a quantitative approach to assess the cumulative effect of multiple variants, with higher scores correlating with more pronounced aging phenotypes . Research models investigating these connections should consider the complex interplay between genetic variants and environmental factors, as well as potential retrograde signaling mechanisms whereby mitochondrial dysfunction triggers adaptive nuclear responses . Future therapeutic interventions targeting these variants could potentially attenuate their effects on premature aging, highlighting the relevance of MT-ND3 research beyond evolutionary studies to biomedical applications in age-related conditions .
Species-Specific Comparison of MT-ND3 Properties
The following table presents a comparative analysis of MT-ND3 protein characteristics across different salmonid species based on available research data:
| Characteristic | Salmo trutta (Brown trout) | Oncorhynchus tshawytscha (Chinook salmon) | Hucho taimen (Siberian taimen) |
|---|---|---|---|
| Protein Length | 116 amino acids (full-length) | Partial length | 116 amino acids (full-length) |
| Expression System | E. coli | E. coli | N/A (native only) |
| Purification Tag | N-terminal His tag | Variable (determined during manufacturing) | N/A |
| Purity | >90% (SDS-PAGE) | >85% (SDS-PAGE) | N/A |
| Storage Stability | 12 months at -20°C/-80°C (lyophilized) | 12 months at -20°C/-80°C (lyophilized) | N/A |
| Amino Acid Sequence | MNLITTIIAITITLSAVLATVSFWLPQITPDAEKLSPYECGFDPLGSARLPFSLRFFLIAIFLLFDLEIALLLPLPWGDQLATPALTLAWSAAVLALLTLGLIYEWTQGGLEWAE | Not provided in source material | Exhibits recombination with Brachymystax species |
| Documented Variants | Limited information available | Limited information available | Shows evidence of introgression with Brachymystax lenok |
Functional Impact Scores of Common MT-ND3 Variants
Recent research has identified several MT-ND3 variants with significant functional impacts. The table below summarizes key non-synonymous variants and their associated functional impact scores:
| Variant | Gene | Amino Acid Change | MutPred Score | mtDNA Selection Score | MitoTool Score | Combined FI Score | Associated Phenotype |
|---|---|---|---|---|---|---|---|
| m.10398A > G | MT-ND3 | Variable | Contributed to combined score | Contributed to combined score | Contributed to combined score | Part of 0.82 (SD = 1.28) mean FI score | Associated with premature aging in young adults |
| Various mutations in MT-ND3 | MT-ND3 | Multiple possible changes | Varies by specific mutation | Varies by specific mutation | Varies by specific mutation | Higher scores correlate with greater pathogenicity | Multiple - including aging phenotypes |
Integrating MT-ND3 Research with Broader Mitochondrial Studies
Expanding MT-ND3 research beyond isolated protein studies requires integration with broader mitochondrial investigations. Researchers should consider implementing multi-omics approaches that combine proteomics, metabolomics, and transcriptomics to understand how MT-ND3 variants influence the entire mitochondrial system . Long-term studies tracking the effects of specific MT-ND3 variants on organismal health and aging can provide valuable insights into the clinical relevance of mutations, particularly given emerging evidence connecting certain variants to premature aging phenotypes . For evolutionary biologists, the documented recombination events in MT-ND3 necessitate careful consideration when using this gene for phylogenetic studies, with recommendations to employ multiple genetic markers to overcome potential misleading signals from introgression events . Additionally, researchers investigating mitochondrial-nuclear communication should explore how MT-ND3 variants may trigger retrograde signaling pathways that alter nuclear gene expression patterns in response to mitochondrial dysfunction . As technologies advance, the development of CRISPR-based approaches for mitochondrial DNA editing may eventually allow for precise manipulation of MT-ND3 sequences in living organisms, opening new avenues for functional validation studies and potential therapeutic interventions.
Emerging Technologies for MT-ND3 Functional Analysis
The advancement of research on MT-ND3 function will benefit from several emerging technologies that extend beyond traditional biochemical approaches. Single-molecule imaging techniques, including high-speed atomic force microscopy, offer unprecedented opportunities to visualize conformational changes in MT-ND3 during electron transport in real-time . The integration of artificial intelligence algorithms with structural prediction tools can enhance our ability to model the effects of specific mutations on protein stability and interactions, generating more accurate functional impact predictions . Nanoscale respirometry systems that measure oxygen consumption in minimal sample volumes will facilitate functional studies of recombinant MT-ND3 variants, enabling high-throughput comparative analyses . Additionally, the development of mitochondria-targeted CRISPR systems, though still in early stages, holds promise for direct editing of MT-ND3 sequences in living cells, potentially allowing researchers to introduce or correct specific variants and observe resultant phenotypes . As these technologies mature, researchers will gain more comprehensive insights into the structural dynamics and functional significance of MT-ND3 within the mitochondrial respiratory chain, advancing our understanding of both evolutionary processes and disease mechanisms.
Translational Applications of MT-ND3 Research Findings
While fundamental research on MT-ND3 continues to yield important insights into mitochondrial biology and evolution, emerging translational applications deserve attention from the research community. The identification of functional impact scores for MT-ND3 variants provides a framework for developing biomarkers of mitochondrial dysfunction that may predict susceptibility to aging-related diseases . Understanding the specific mechanisms by which MT-ND3 variants influence respiratory chain efficiency could inform therapeutic approaches targeting mitochondrial function in conditions characterized by bioenergetic deficiencies . For conservation biologists, the documented instances of mtDNA recombination in MT-ND3 highlight the need for refined approaches to species identification and population monitoring, particularly in managed fisheries where accurate genetic identification is crucial . Additionally, comparative studies across species with different longevity profiles may reveal how natural selection has shaped MT-ND3 sequence variation to optimize mitochondrial function for specific ecological niches and life history strategies . As research progresses, the development of small molecule modulators that can specifically interact with MT-ND3 to enhance or restore compromised function represents an exciting frontier with potential applications in both research and therapeutic contexts.
