Recombinant Didelphis marsupialis virginiana NADH-ubiquinone oxidoreductase chain 4L (MT-ND4L)
Description
Introduction to MT-ND4L
NADH-ubiquinone oxidoreductase chain 4L (MT-ND4L) is a critical component of the mitochondrial respiratory chain, specifically functioning as a subunit of Complex I. This protein is encoded by the mitochondrial genome and plays an essential role in cellular energy production through oxidative phosphorylation . The recombinant form of this protein from the Virginia opossum (Didelphis marsupialis virginiana) provides researchers with opportunities to study comparative mitochondrial biology and evolutionary adaptations in energy metabolism.
Complex I, also known as NADH dehydrogenase, represents the largest of the five complexes in the electron transport chain and is located within the inner mitochondrial membrane . As one of the core subunits of this complex, MT-ND4L contributes significantly to the process of converting energy from nutrients into ATP, the primary energy currency of cells.
Molecular Structure and Characteristics
The MT-ND4L gene in humans is located in the mitochondrial DNA from base pair 10,469 to 10,765 . The gene produces a relatively small protein of approximately 11 kDa composed of 98 amino acids . While the specific genomic coordinates for the Virginia opossum MT-ND4L gene are not detailed in the current literature, the protein likely shares some structural similarities with its human counterpart due to the conserved nature of mitochondrial proteins across mammalian species.
An interesting structural feature of the human MT-ND4L gene is its unusual 7-nucleotide overlap with the MT-ND4 gene, where the last three codons of MT-ND4L (encoding Gln, Cys, and Stop) overlap with the first three codons of MT-ND4 (encoding Met, Leu, and Lys) . This overlapping gene arrangement represents an evolutionary adaptation to maximize information content within the compact mitochondrial genome.
MT-ND4L belongs to a group of seven mitochondrially encoded subunits of Complex I, which also includes MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND5, and MT-ND6 . These mitochondrially encoded subunits are characterized by their high hydrophobicity and form the core of the transmembrane region of Complex I . The hydrophobic nature of these proteins reflects their function within the lipid environment of the mitochondrial membrane.
Table 1: General Characteristics of MT-ND4L
Functional Role in Mitochondrial Respiration
The MT-ND4L protein serves as a critical subunit of respiratory chain Complex I, which catalyzes NADH dehydrogenation and electron transfer to ubiquinone (coenzyme Q10) . This represents the first step in the electron transport chain, a process fundamental to cellular energy production.
The electron transfer process begins when NADH binds to Complex I and transfers two electrons to the flavin mononucleotide (FMN) prosthetic arm, forming FMNH₂ . These electrons then travel through a series of iron-sulfur (Fe-S) clusters before ultimately reducing coenzyme Q10 to ubiquinol (CoQH₂) . This electron flow causes conformational changes in the protein complex and shifts in redox state, resulting in the pumping of four hydrogen ions out of the mitochondrial matrix .
MT-ND4L is believed to belong to the minimal assembly of core proteins required for this catalytic activity . The protein contributes to both the structural integrity of Complex I and its functional capacity to transfer electrons and pump protons across the inner mitochondrial membrane, generating the electrochemical gradient that drives ATP synthesis.
Recombinant Protein Production and Characteristics
Recombinant protein technology enables the production of specific proteins outside their native biological context, facilitating detailed structural and functional studies. For the production of recombinant MT-ND4L from Didelphis marsupialis virginiana, various expression systems may be employed, including E. coli, yeast, baculovirus, or mammalian cell cultures .
The production process typically involves cloning the MT-ND4L gene from Virginia opossum mitochondrial DNA, inserting it into an appropriate expression vector, and transforming or transfecting the chosen host system. Following expression, the recombinant protein undergoes purification to achieve high purity levels (typically >90%) .
The purified recombinant protein is generally stored in a liquid formulation containing glycerol, which helps maintain stability during storage. For extended preservation, the protein may be stored at -20°C or -80°C .
Table 2: Recombinant Protein Production Parameters
Comparative Biochemistry in Opossums
While specific studies on MT-ND4L from Didelphis marsupialis virginiana appear limited in the current literature, research on other proteins from this species provides insights into the comparative biochemistry between opossums and other mammals. For instance, studies on erythrocyte glucose-6-phosphate dehydrogenase (G6PD) from the Brazilian opossum (Didelphis marsupialis) have revealed interesting comparative differences with human counterparts .
Interestingly, despite these differences in specific activity, the kinetic properties of the opossum G6PD were similar to those of the human enzyme, with comparable Michaelis-Menten constants for glucose-6-phosphate and nicotinamide adenine dinucleotide phosphate . This pattern of conserved kinetic properties alongside species-specific differences in expression levels or stability might also apply to other proteins, including MT-ND4L.
Table 3: Comparative Analysis of G6PD from Didelphis marsupialis and Human
Clinical and Research Significance
The study of MT-ND4L across different species, including marsupials like the Virginia opossum, has significant implications for both evolutionary biology and medical research. In humans, variants in MT-ND4L have been associated with increased BMI in adults and implicated in metabolic disorders including obesity, diabetes, and hypertension .
Most notably, a specific T>C mutation at position 10,663 in the human MT-ND4L gene is known to cause Leber's Hereditary Optic Neuropathy (LHON) . This mutation results in the replacement of valine with alanine at position 65 of the protein, disrupting Complex I function in the electron transport chain . While the exact mechanism by which this mutation leads to vision loss remains uncertain, it likely involves disrupted ATP production due to impaired Complex I activity .
Comparative studies involving recombinant MT-ND4L from Virginia opossum could provide valuable insights into the evolutionary conservation of functionally critical residues and potentially identify structural features that confer resistance to pathogenic mutations. Such research could contribute to our understanding of mitochondrial disorders and potentially inform therapeutic strategies.
Future Research Directions
The production and characterization of recombinant Didelphis marsupialis virginiana MT-ND4L opens several promising avenues for future research:
-
Comparative genomic analysis of the MT-ND4L gene across marsupial species to identify evolutionary conservation patterns and species-specific adaptations.
-
Structural determination using cryo-electron microscopy or X-ray crystallography to elucidate the three-dimensional structure of opossum MT-ND4L within Complex I.
-
Functional studies comparing the electron transfer efficiency and proton pumping capacity of Complex I containing opossum versus human MT-ND4L.
-
Investigation of potential species-specific adaptations in marsupial mitochondrial function that might confer metabolic advantages or resilience to environmental stressors.
-
Development of models to study mitochondrial disorders using recombinant proteins from diverse species, potentially revealing alternative functional mechanisms or compensatory pathways.
Product Specs
Please note: We prioritize shipping the format currently in stock. However, if you have a specific format requirement, please include it in your order notes, and we will accommodate your request.
Note: All our proteins are shipped with standard blue ice packs. If you require dry ice shipping, please inform 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 MT-ND4L and what is its role in mitochondrial function?
MT-ND4L (mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4L) serves as a core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I). This protein catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor. It forms part of the enzyme membrane arm embedded in the lipid bilayer and is critically involved in proton translocation across the inner mitochondrial membrane .
The protein functions within Complex I, which is the first and largest enzyme complex in the electron transport chain, playing a vital role in cellular energy production through oxidative phosphorylation. Researchers should note that dysfunction in this protein can significantly impact ATP production and may contribute to mitochondrial disorders.
How evolutionarily conserved is MT-ND4L across different species?
MT-ND4L shows varying degrees of conservation across species due to its essential role in mitochondrial function. Comparative analysis reveals specific regions of higher conservation, particularly in the transmembrane domains. In phylogenetic studies, MT-ND4L has been used alongside other mitochondrial genes to establish evolutionary relationships between species .
Notably, mtDNA-like sequences, including those related to MT-ND4L, have been found in the nuclear genome of the opossum genus Didelphis, suggesting that mitochondrial DNA migration to the nuclear genome occurred multiple times during Didelphis evolution . This finding has significant implications for understanding the complex interplay between nuclear and mitochondrial genomes.
What are the optimal methods for isolating and purifying recombinant MT-ND4L from expression systems?
Isolating functional MT-ND4L presents significant challenges due to its hydrophobic nature and membrane integration. A multistep approach is recommended:
-
Expression System Selection: Bacterial systems (E. coli) with specialized strains designed for membrane proteins are commonly used, though eukaryotic systems may provide better post-translational modifications.
-
Solubilization Protocol: Use a gentle detergent gradient approach, starting with:
-
Initial membrane solubilization with 1-2% n-dodecyl β-D-maltoside (DDM)
-
Purification buffers containing 0.05-0.1% DDM to maintain protein stability
-
-
Purification Strategy:
-
Immobilized metal affinity chromatography (IMAC) with His-tagged constructs
-
Size exclusion chromatography for further purification
-
Consider using amphipols or nanodiscs for final stabilization
-
For functional studies, researchers should verify protein integrity through circular dichroism and activity assays measuring NADH:ubiquinone oxidoreductase activity.
What PCR and sequencing strategies are most effective for studying MT-ND4L variants?
Based on methodologies used in mitochondrial genome research, the following approach is recommended for studying MT-ND4L variants:
-
DNA Extraction: Purify mitochondrial DNA from tissue samples using differential centrifugation to remove nuclear debris, followed by standard alkaline lysis and phenol/chloroform extraction .
-
PCR Amplification: Design primers that flank the MT-ND4L gene. For challenging amplifications, use long-range PCR systems (such as Expand long template PCR system) with the following parameters:
-
Cloning and Sequencing: Clone PCR products into appropriate vectors (pGEM-T or similar) and sequence using both universal and gene-specific primers. Next-generation sequencing approaches may be more efficient for population studies .
-
Variant Analysis: Compare sequences using alignment tools like CLUSTAL W, followed by refined analysis based on deduced amino acid sequences and predicted secondary structures .
How can researchers accurately assess the functional impact of MT-ND4L mutations?
Assessing functional impacts of MT-ND4L mutations requires a multi-level approach:
-
In silico analysis:
-
Biochemical characterization:
-
Complex I activity assays measuring NADH oxidation rates
-
Membrane potential measurements using fluorescent dyes
-
Respiratory capacity assessment in intact cells or isolated mitochondria
-
-
Cellular phenotyping:
-
ROS production measurement
-
ATP synthesis quantification
-
Cell viability under metabolic stress conditions
-
-
Integration with clinical/phenotypic data:
-
For disease-associated variants, correlation with clinical manifestations
-
Population frequency analysis to distinguish rare pathogenic from common polymorphisms
-
For example, molecular dynamics simulations have been used to compare wild-type proteins with mutants, revealing that certain mutations affect loop flexibility significantly, potentially disrupting crucial interactions between loop residues and nearby subunits .
How do nuclear-encoded mtDNA-like sequences (NUMTs) of MT-ND4L impact mitochondrial genetics research?
The discovery of mtDNA-like sequences in the nuclear genome of Didelphis presents significant methodological challenges and research opportunities:
What is the association between MT-ND4L variants and neurodegenerative disorders?
Recent studies have established significant connections between MT-ND4L variants and neurodegenerative conditions:
-
Alzheimer's Disease Association:
-
A study using whole exome sequencing from 10,831 participants in the Alzheimer's Disease Sequencing Project identified a significant association between AD risk and a rare MT-ND4L variant (rs28709356 C>T; minor allele frequency = 0.002; P = 7.3 × 10−5) .
-
Gene-based testing also revealed significant association with MT-ND4L (P = 6.71 × 10−5) .
-
These findings suggest mitochondrial dysfunction may be a contributing factor in AD pathogenesis.
-
-
Potential Mechanisms:
-
MT-ND4L mutations may impair Complex I function, leading to:
-
Reduced ATP production
-
Increased reactive oxygen species generation
-
Altered calcium homeostasis
-
Compromised mitochondrial dynamics
-
-
-
Research Implications:
-
Investigators should consider mitochondrial genetic factors in neurodegenerative disease studies.
-
Therapeutic strategies targeting mitochondrial function may offer novel approaches for neurodegenerative disorders.
-
How can phylogenetic analysis of MT-ND4L contribute to evolutionary studies?
MT-ND4L sequence analysis has proven valuable for evolutionary studies:
-
Resolving Phylogenetic Relationships:
-
Methodological Approach:
-
Extract and sequence complete mitochondrial genomes from target species.
-
Align sequences using programs like CLUSTAL W and refine based on amino acid sequences.
-
Conduct phylogenetic analyses using maximum likelihood or Bayesian methods.
-
Evaluate statistical support for different topologies.
-
-
Research Example:
What are the major challenges in working with recombinant MT-ND4L and how can they be addressed?
Researchers face several challenges when working with MT-ND4L:
-
Protein Expression Challenges:
-
Hydrophobicity and membrane integration cause poor expression yields.
-
Solution: Use specialized expression systems such as C41/C43 E. coli strains designed for membrane proteins. Optimize codon usage for the expression host and consider fusion tags that enhance solubility.
-
-
Protein Stability Issues:
-
MT-ND4L tends to aggregate when removed from its native lipid environment.
-
Solution: Maintain an appropriate detergent concentration throughout all purification steps. Consider reconstitution into nanodiscs or liposomes for functional studies.
-
-
Functional Assay Limitations:
-
Isolating MT-ND4L from its Complex I context may result in loss of function.
-
Solution: Consider co-expression with interacting subunits or use partial complex reconstitution approaches. Develop specialized activity assays that account for the protein's native environment.
-
-
Structural Characterization Difficulties:
-
Traditional structural biology techniques may be challenging to apply.
-
Solution: Employ cryo-electron microscopy for structural studies, potentially in the context of the larger Complex I. NMR studies using selectively labeled proteins in membrane mimetics may provide local structural information.
-
How can researchers distinguish between potential artifacts and true mitochondrial variants when analyzing MT-ND4L?
Distinguishing authentic mitochondrial variants from artifacts requires careful methodological approaches:
-
Sources of Potential Artifacts:
-
Nuclear mitochondrial DNA segments (NUMTs) co-amplification
-
PCR and sequencing errors
-
Heteroplasmy misinterpretation
-
Sample contamination
-
-
Recommended Validation Approach:
-
Multiple Tissue Sampling: Compare results across different tissue types, as NUMTs will be consistent while true heteroplasmy may vary.
-
Depth of Sequencing: Use high-coverage sequencing to distinguish low-level heteroplasmy from sequencing errors.
-
Independent Methodologies: Confirm findings using different primer sets and sequencing technologies.
-
Functional Validation: When possible, assess the biochemical impact of identified variants.
-
-
Data Analysis Considerations:
What emerging technologies could advance MT-ND4L research?
Several cutting-edge technologies show promise for advancing MT-ND4L research:
-
CRISPR-based Mitochondrial Genome Editing:
-
Recent developments in mitochondrial-targeted nucleases may enable precise editing of MT-ND4L.
-
This would allow creation of isogenic cell lines differing only in specific MT-ND4L variants.
-
-
Single-Cell Mitochondrial Omics:
-
Emerging technologies for single-cell resolution of mitochondrial heteroplasmy could reveal tissue-specific patterns of MT-ND4L variants.
-
Integration with spatial transcriptomics could map mitochondrial function to specific cellular microenvironments.
-
-
Advanced Structural Biology Approaches:
-
Cryo-electron tomography of intact mitochondria could reveal MT-ND4L in its native context.
-
Time-resolved structural studies may capture dynamic conformational changes during the catalytic cycle.
-
-
Systems Biology Integration:
-
Multi-omics approaches integrating proteomics, metabolomics, and genomics could provide a comprehensive view of how MT-ND4L variants affect cellular physiology.
-
Mathematical modeling of mitochondrial function incorporating MT-ND4L variant effects could predict cellular energetic outcomes.
-
How might MT-ND4L research contribute to understanding the mitochondrial basis of disease?
MT-ND4L research has significant potential to advance our understanding of mitochondrial contributions to disease:
-
Neurodegenerative Disease Mechanisms:
-
Metabolic Disorders:
-
As a component of Complex I, MT-ND4L function directly impacts cellular energy metabolism.
-
Research into how variants affect this function could provide insights into metabolic disorders.
-
-
Aging Processes:
-
Mitochondrial dysfunction is implicated in aging processes.
-
Understanding how MT-ND4L variants accumulate over time and affect cellular function could contribute to healthy aging research.
-
-
Precision Medicine Applications:
-
Characterization of MT-ND4L variants could contribute to personalized medicine approaches for mitochondrial disorders.
-
Therapeutic strategies targeting specific dysfunction caused by variants could be developed.
-
