Recombinant Odobenus rosmarus rosmarus NADH-ubiquinone oxidoreductase chain 4L (MT-ND4L)

What is MT-ND4L and what is its function in mitochondria?

MT-ND4L (NADH-ubiquinone oxidoreductase chain 4L) is a protein encoded by the mitochondrial genome that functions as a subunit of Complex I (NADH dehydrogenase) in the electron transport chain. This protein is critical for the first step of electron transport, transferring electrons from NADH to ubiquinone during oxidative phosphorylation. Complex I creates an electrochemical gradient across the inner mitochondrial membrane by pumping protons, which ultimately drives ATP synthesis .

The MT-ND4L protein is highly hydrophobic and forms part of the core transmembrane region of Complex I, which has an L-shaped structure with a hydrophobic transmembrane domain and a hydrophilic peripheral arm. This architecture is essential for the proper functioning of the complex in energy production within mitochondria .

What are the structural characteristics of Atlantic walrus (Odobenus rosmarus rosmarus) MT-ND4L?

The recombinant Odobenus rosmarus rosmarus MT-ND4L protein consists of 98 amino acids with a full expression region of 1-98. Its amino acid sequence is: MSMVYANIFMAFVVSLMGMLVYRSHLMSSLLCLEGMMLSLFVMMSVTILNNHFTLANMAPIILLVFAACEAALGLSLLVMVSNTYGTDYVQNLNLLQC .

The protein has been identified in UniProt database with accession number Q8LWS1. Like its human counterpart, Atlantic walrus MT-ND4L is part of Complex I in the mitochondrial respiratory chain and shares structural similarities with other mammalian homologs. The protein is generally stored in a Tris-based buffer with 50% glycerol to maintain its stability .

How is recombinant MT-ND4L protein produced for research applications?

Recombinant MT-ND4L protein production typically involves several methodological steps:

• Gene synthesis or cloning from Atlantic walrus mitochondrial DNA

• Insertion into an appropriate expression vector with a tag system (determined during production)

• Transformation into a bacterial, yeast, or mammalian expression system

• Induction of protein expression

• Cell lysis and protein extraction

• Purification using affinity chromatography based on the attached tag

• Quality control testing including SDS-PAGE, Western blotting, and activity assays

• Final formulation in an appropriate buffer system (Tris-based with 50% glycerol)

The challenge in producing MT-ND4L lies in its highly hydrophobic nature, which often requires specialized expression systems and purification techniques to maintain proper folding and stability.

What is the difference between MT-ND4L and other mitochondrial-encoded Complex I subunits?

MT-ND4L is one of seven mitochondrially-encoded subunits of Complex I, along with MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND5, and MT-ND6. While all these subunits are essential components of the same complex, they differ in several important ways:

A unique feature of MT-ND4L is its unusual gene structure. In humans, and likely conserved in other mammals including Atlantic walrus, the MT-ND4L gene has a 7-nucleotide overlap with the MT-ND4 gene. The last three codons of MT-ND4L overlap with the first three codons of MT-ND4 but in different reading frames .

What experimental approaches can be used to study MT-ND4L function in comparative species analysis?

Studying MT-ND4L function across species requires sophisticated experimental approaches:

• Blue Native Polyacrylamide Gel Electrophoresis (BN-PAGE): This technique allows isolation and analysis of intact mitochondrial complexes to compare Complex I assembly and stability across species.

• Oxygen Consumption Analysis: Using high-resolution respirometry to measure oxygen consumption rates in isolated mitochondria or cells expressing different species' MT-ND4L can reveal functional differences in OXPHOS efficiency.

• Site-Directed Mutagenesis: Creating specific mutations in conserved or divergent residues between species can identify functionally critical amino acids specific to marine mammals like the Atlantic walrus.

• Homology Modeling and Molecular Dynamics Simulations: Computational approaches to predict structural differences between species' MT-ND4L proteins and their impacts on Complex I function.

• Complementation Studies: Expressing Atlantic walrus MT-ND4L in human or mouse cell lines with MT-ND4L deficiency to assess functional complementation across species.

Methodologically, researchers should isolate mitochondria from relevant tissues using differential centrifugation, followed by gentle solubilization with digitonin or n-dodecyl-β-D-maltoside to preserve Complex I integrity. Subsequent analysis using the techniques above can reveal species-specific adaptations in MT-ND4L function .

How do mutations in MT-ND4L affect Complex I assembly and function, and what methodologies best detect these effects?

Mutations in MT-ND4L can significantly impact Complex I assembly and function through several mechanisms. To study these effects, researchers can employ these methodologies:

• Complex I In-Gel Activity Assays: BN-PAGE gels incubated with NADH and nitrotetrazolium blue can visualize Complex I activity directly in the gel, allowing comparison between wild-type and mutant forms.

• Proximity Labeling Techniques: Using APEX2 or BioID fused to MT-ND4L to identify altered protein-protein interactions resulting from mutations.

• Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS): To detect structural changes in Complex I caused by MT-ND4L mutations.

• Cryo-EM Analysis: For high-resolution structural analysis of wild-type versus mutant Complex I containing altered MT-ND4L.

• Mitochondrial ROS Production Measurement: Using specific fluorescent probes like MitoSOX to quantify superoxide production resulting from Complex I dysfunction.

When analyzing the T10663C (Val65Ala) mutation associated with Leber hereditary optic neuropathy, researchers observed decreased Complex I activity without significant changes in protein levels, suggesting this mutation affects function rather than assembly. Similar approaches can be applied to study other mutations or species-specific variants of MT-ND4L .

What techniques are most effective for studying the interaction between recombinant MT-ND4L and other Complex I subunits?

Several sophisticated techniques can effectively study interactions between recombinant MT-ND4L and other Complex I subunits:

• Crosslinking Mass Spectrometry (XL-MS): Chemical crosslinking followed by mass spectrometry analysis can identify interaction sites between MT-ND4L and neighboring subunits.

• Surface Plasmon Resonance (SPR): This technique can measure binding kinetics between purified recombinant MT-ND4L and other Complex I subunits.

• Förster Resonance Energy Transfer (FRET): By tagging MT-ND4L and potential interaction partners with appropriate fluorophores, researchers can detect proximity and interaction in reconstituted systems or in vitro.

• Co-immunoprecipitation with Targeted Antibodies: Using antibodies specific to MT-ND4L to pull down interacting partners, followed by proteomic analysis.

• Reconstitution Studies: Systematic assembly of Complex I subunits in liposomes or nanodiscs with and without MT-ND4L to determine its role in complex formation.

These interaction studies are particularly challenging due to the hydrophobic nature of MT-ND4L and its integration in the inner mitochondrial membrane. Researchers typically use mild detergents like digitonin or specialized membrane mimetics like nanodiscs to maintain the protein in a near-native environment during analysis .

How do post-translational modifications affect MT-ND4L function and what analytical methods can detect these modifications?

Post-translational modifications (PTMs) of MT-ND4L can significantly impact its function within Complex I. To study these modifications, researchers can employ these analytical methods:

• High-Resolution Mass Spectrometry: Targeted LC-MS/MS analysis can identify and quantify specific PTMs on MT-ND4L, including phosphorylation, acetylation, and oxidative modifications.

• Site-Specific Antibodies: Development of antibodies that recognize specific modified forms of MT-ND4L for western blotting and immunoprecipitation.

• Protein Microarrays: To screen for multiple potential PTMs simultaneously across different experimental conditions.

• Targeted Mutagenesis: Creating non-modifiable mutants (e.g., Ser to Ala) to assess the functional significance of specific modifications.

• Chemical Reporters and Click Chemistry: Using bio-orthogonal labeling strategies to detect and enrich for specific PTMs.

The experimental design should include appropriate controls to distinguish species-specific modifications from those that might occur during the recombinant protein production process. Researchers should also consider how the highly hydrophobic nature of MT-ND4L might affect the accessibility of certain residues to modifying enzymes in vivo .

What are the best storage and handling conditions for recombinant Odobenus rosmarus rosmarus MT-ND4L protein?

Proper storage and handling of recombinant Odobenus rosmarus rosmarus MT-ND4L protein is critical for maintaining its structural integrity and functional properties:

• Storage Temperature: Store at -20°C for regular use, or at -80°C for extended storage to minimize protein degradation.

• Buffer Composition: The protein is typically maintained in a Tris-based buffer supplemented with 50% glycerol that has been optimized for this specific protein.

• Aliquoting Recommendations: Divide the protein into small working aliquots before freezing to avoid repeated freeze-thaw cycles. Working aliquots can be stored at 4°C for up to one week.

• Freeze-Thaw Considerations: Repeated freezing and thawing should be avoided as it can lead to protein denaturation, especially for membrane proteins like MT-ND4L.

• Handling During Experiments: When using the protein for experiments, maintain it on ice and use freshly thawed aliquots whenever possible.

• Quality Control: Periodically verify protein integrity using SDS-PAGE and activity assays, especially after extended storage periods .

What experimental controls should be included when studying recombinant MT-ND4L in functional assays?

Rigorous experimental design for functional assays involving recombinant MT-ND4L should include these essential controls:

• Positive Control: Include a well-characterized MT-ND4L protein with known activity, preferably from a closely related species.

• Negative Control: Use a denatured version of the same recombinant protein (heat-treated or chemically denatured) to establish baseline measurements.

• Empty Vector Control: When expressing the protein in cellular systems, include cells transformed with the empty expression vector.

• Tag-Only Control: Include a control protein expressing only the tag used for MT-ND4L purification to account for tag-related effects.

• Inhibitor Controls: Use specific Complex I inhibitors like rotenone to confirm that observed activities are specifically due to Complex I function.

• Species Cross-Reactivity Controls: When studying Atlantic walrus MT-ND4L in heterologous systems, include tests for cross-species compatibility.

• Concentration Gradient: Perform assays with varying concentrations of the recombinant protein to establish dose-response relationships.

In addition, researchers should verify protein purity by SDS-PAGE and western blotting prior to functional assays and standardize all protein quantification methods to ensure comparable results across experiments .

How can researchers differentiate between MT-ND4L dysfunction and other mitochondrial defects in experimental systems?

Differentiating MT-ND4L-specific dysfunction from other mitochondrial defects requires systematic analysis using multiple complementary approaches:

These approaches can be combined in a decision tree format, starting with general assays of mitochondrial function and progressively focusing on Complex I and finally MT-ND4L-specific tests to ensure accurate attribution of dysfunction .

How does Atlantic walrus MT-ND4L differ from other marine and terrestrial mammals, and what methodologies best reveal these differences?

Comparative analysis of MT-ND4L across marine and terrestrial mammals reveals evolutionary adaptations that may reflect different metabolic demands and environmental pressures:

• Sequence Alignment Analysis: Multiple sequence alignment of MT-ND4L from diverse mammalian species reveals conservation patterns and marine mammal-specific variations. Key tools include CLUSTALW, MUSCLE, and T-COFFEE for alignment, followed by visualization in Jalview or similar software.

• Phylogenetic Analysis: Maximum likelihood or Bayesian methods to construct evolutionary trees based on MT-ND4L sequences, revealing convergent evolution in marine mammals.

• Selection Analysis: Tests for positive selection (dN/dS ratio analysis) using PAML or HyPhy to identify amino acid positions under selection in marine mammals.

• Structural Prediction Comparisons: Homology modeling of MT-ND4L from different species using AlphaFold or similar tools, followed by structural comparisons to identify functionally significant differences.

• Ancestral Sequence Reconstruction: Computational inference of ancestral MT-ND4L sequences to track evolutionary changes along lineages leading to marine adaptation.

Walrus MT-ND4L likely shows adaptations that reflect the high oxygen demands of diving, potentially including modifications that enhance Complex I efficiency under hypoxic conditions or reduce reactive oxygen species production. These adaptations may be convergent with other marine mammals like whales and seals, despite their separate evolutionary origins .

What experimental designs can effectively assess the functional significance of species-specific amino acid substitutions in MT-ND4L?

To assess the functional significance of species-specific amino acid substitutions in Atlantic walrus MT-ND4L, researchers can implement these experimental designs:

• Site-Directed Mutagenesis and Heterologous Expression:

  • Create constructs with walrus-specific amino acids introduced into human MT-ND4L

  • Express in human cell lines with MT-ND4L deficiency

  • Measure Complex I activity, ROS production, and assembly

• Transmitochondrial Cybrid Approaches:

  • Generate cybrid cell lines containing mitochondria from different species

  • Compare functional parameters across cybrid lines

  • Identify performance differences attributable to MT-ND4L variations

• In Vitro Reconstitution with Purified Components:

  • Reconstitute Complex I with different species' MT-ND4L variants

  • Measure electron transfer rates and proton pumping efficiency

  • Identify functional differences under varying conditions (temperature, pH, salt)

• Thermal Stability Assays:

  • Compare thermal denaturation profiles of Complex I containing different MT-ND4L variants

  • Identify species-specific adaptations in protein stability

• Computational Analysis Combined with Experimental Validation:

  • Use molecular dynamics simulations to predict functional effects of substitutions

  • Experimentally validate predictions using the methods above

These approaches should be implemented under conditions that mimic physiological stresses relevant to marine mammals, such as hypoxia, pressure changes, and temperature variations to reveal adaptations specific to the Atlantic walrus environment .

How can mitochondrial isolation techniques be optimized for studying MT-ND4L in tissues from marine mammals?

Mitochondrial isolation from marine mammal tissues presents unique challenges that require specialized techniques:

• Tissue Preservation Protocol:

  • Immediate flash-freezing in liquid nitrogen upon collection

  • Storage at -80°C with protease and phosphatase inhibitors

  • Transport in specialized containers maintaining ultra-low temperatures

• Modified Isolation Buffers:

  • Adjust ionic composition to match marine mammal intracellular environment

  • Include higher concentrations of antioxidants to prevent oxidation of polyunsaturated fatty acids abundant in marine mammals

  • Use sucrose-based buffers with optimized osmolarity for marine mammal cells

• Gentle Homogenization Techniques:

  • Use Dounce homogenization with reduced strokes to prevent damage to fragile mitochondria

  • Implement nitrogen cavitation as an alternative to mechanical disruption

  • Optimize homogenization speed and duration for specific marine mammal tissues

• Density Gradient Purification:

  • Use Percoll or sucrose gradients specifically calibrated for marine mammal mitochondria

  • Adjust centrifugation speeds and times to account for different mitochondrial densities

• Functional Assessment Immediately After Isolation:

  • Conduct respiratory measurements promptly to capture native functional state

  • Implement quality control metrics specific to marine mammal mitochondria

• Cryopreservation Protocols:

  • Develop specialized cryopreservation methods if immediate analysis is not possible

  • Test different cryoprotectants for optimal preservation of marine mammal mitochondria

These optimized approaches should be validated using electron microscopy and functional assays to ensure isolated mitochondria maintain their structural integrity and metabolic activity .

What is known about MT-ND4L mutations and their role in mitochondrial diseases, and how can this inform comparative studies?

Mutations in the MT-ND4L gene have been associated with several mitochondrial disorders, providing valuable insights for comparative studies:

• Leber Hereditary Optic Neuropathy (LHON): The T10663C (Val65Ala) mutation in human MT-ND4L has been identified in families with LHON, causing vision loss through degeneration of retinal ganglion cells and the optic nerve. This mutation changes a highly conserved valine to alanine at position 65 of the protein .

• Association with Body Mass Index (BMI): Variants of human MT-ND4L have been associated with increased BMI in adults, suggesting a role in metabolic regulation .

• Research Methodologies:

  • Patient sample analysis through next-generation sequencing

  • Functional studies in cybrid cell lines

  • Biochemical analysis of Complex I activity

  • ROS production measurement in patient-derived cells

• Comparative Study Applications:

  • Examination of conservation of disease-associated residues across species

  • Analysis of natural variations at disease sites in diverse species

  • Investigation of potential compensatory mechanisms in species with variants at disease-associated positions

• Research Questions for Comparative Studies:

  • Does the Atlantic walrus MT-ND4L contain natural variations at positions associated with human disease?

  • Have marine mammals evolved protective mechanisms against pathogenic effects of MT-ND4L variations?

  • Can comparative analysis of MT-ND4L across species reveal potential therapeutic targets for human mitochondrial diseases?

Understanding disease-associated mutations provides crucial insight into functionally important regions of MT-ND4L and can guide the design of comparative studies focused on these regions .

What protocols are most effective for measuring the impact of MT-ND4L variations on reactive oxygen species production?

Measuring reactive oxygen species (ROS) production resulting from MT-ND4L variations requires sensitive and specific methodologies:

• Fluorescent Probe-Based Assays:

  • MitoSOX Red: Specific for mitochondrial superoxide detection

  • DCF-DA: For general cellular hydrogen peroxide measurement

  • Amplex Red: For highly sensitive extracellular hydrogen peroxide detection

  • Dihydroethidium (DHE): For cytosolic superoxide detection

• Experimental Setup:

  • Compare isolated mitochondria containing wild-type vs. variant MT-ND4L

  • Measure ROS production under different substrate conditions (NADH, succinate)

  • Use specific inhibitors (rotenone, antimycin A) to pinpoint ROS source

• Genetically-Encoded ROS Sensors:

  • HyPer: Ratiometric hydrogen peroxide sensor

  • roGFP: Redox-sensitive GFP variants

  • MitoTimer: Mitochondrial oxidative stress reporter

• Electron Paramagnetic Resonance (EPR) Spectroscopy:

  • Use spin traps like DMPO to detect and quantify short-lived free radicals

  • Provides highly specific identification of radical species

• Protocol Considerations:

  • Control for mitochondrial content and membrane potential

  • Perform measurements at physiologically relevant oxygen concentrations

  • Include time-course measurements to capture ROS dynamics

  • Normalize results to protein content or mitochondrial mass

• Data Analysis:

  • Use appropriate statistical methods for time-series data

  • Account for photobleaching and probe auto-oxidation

  • Compare relative rather than absolute values between experiments

These methodologies can reveal how specific variations in MT-ND4L affect ROS production, which may be particularly relevant for understanding adaptations in diving mammals like the Atlantic walrus that experience regular cycles of hypoxia and reoxygenation .

How can researchers effectively model the impact of MT-ND4L variations on mitochondrial function across different tissue types?

Modeling MT-ND4L variations across different tissue types requires a multi-faceted approach combining experimental and computational methods:

• Tissue-Specific Cell Models:

  • Differentiate induced pluripotent stem cells (iPSCs) into relevant tissue types (neurons, cardiomyocytes, skeletal muscle)

  • Introduce MT-ND4L variations using mitochondrial-targeted nucleases or cybrid approaches

  • Measure tissue-specific parameters (neurite outgrowth, contractility, fatigue resistance)

• 3D Organoid Models:

  • Develop tissue-specific organoids containing MT-ND4L variations

  • Assess functional parameters in a more physiologically relevant context

  • Compare organoids derived from different tissue sources

• Tissue-Specific Gene Expression Analysis:

  • RNA-Seq to identify tissue-specific patterns of nuclear gene expression in response to MT-ND4L variations

  • Proteomics to detect tissue-specific compensatory mechanisms

  • Metabolomics to characterize tissue-specific metabolic adaptations

• Computational Modeling:

  • Flux balance analysis (FBA) of tissue-specific metabolic networks

  • Agent-based modeling of mitochondrial dynamics in different cell types

  • In silico prediction of tissue-specific phenotypes based on energy demands

• Integration of Multi-Omics Data:

  • Combine transcriptomic, proteomic, and metabolomic data in tissue-specific models

  • Identify tissue-specific vulnerabilities to MT-ND4L dysfunction

  • Predict compensatory pathways activated in different tissues

• Ex Vivo Tissue Analysis:

  • Utilize tissue explants with introduced MT-ND4L variations

  • Measure tissue-specific respiratory parameters and ROS production

  • Compare responses to metabolic challenges across tissues

This integrated approach can reveal how the same MT-ND4L variation might differentially affect tissues with varying energy demands and mitochondrial content, providing insight into both pathological mechanisms and adaptive responses .

What are the challenges and solutions for expressing and purifying recombinant MT-ND4L for structural studies?

Expressing and purifying hydrophobic membrane proteins like MT-ND4L presents significant technical challenges that require specialized approaches:

• Expression System Selection:

  • Bacterial systems (E. coli): Limited by proper folding and toxic effects

  • Yeast systems (P. pastoris): Better for membrane proteins but lower yields

  • Insect cell systems: Superior folding but more expensive

  • Cell-free systems: Avoid toxicity issues but require optimization for membrane proteins

• Expression Strategies:

  • Fusion with solubility-enhancing tags (MBP, SUMO, Trx)

  • Codon optimization for expression host

  • Inducible promoters with fine-tuned expression levels

  • Co-expression with chaperones to improve folding

• Membrane Mimetic Environments:

  • Detergent screening (DDM, LMNG, digitonin)

  • Lipid nanodiscs for native-like environment

  • Amphipols for increased stability

  • Styrene maleic acid lipid particles (SMALPs) for detergent-free extraction

• Purification Approaches:

  • Tandem affinity tags for higher purity

  • Size exclusion chromatography to remove aggregates

  • Ion exchange chromatography for final polishing

  • On-column detergent exchange during purification

• Stability Assessment and Optimization:

  • Thermal shift assays to identify stabilizing conditions

  • Limited proteolysis to identify flexible regions

  • Stability screening with various lipids and detergents

  • Engineering stabilizing mutations based on comparative analysis

• Quality Control Methods:

  • Circular dichroism to verify secondary structure

  • Dynamic light scattering to assess homogeneity

  • Negative-stain electron microscopy for structural integrity

  • Mass spectrometry for accurate mass determination

These methodologies must be adapted specifically for Atlantic walrus MT-ND4L, considering its unique sequence properties and potentially using insights from successfully expressed homologs from other species .

How can researchers effectively study the interaction between MT-ND4L and the mitochondrial lipid environment?

The interaction between MT-ND4L and the mitochondrial lipid environment is crucial for understanding its function, requiring specialized techniques:

• Native Mass Spectrometry:

  • Analyze MT-ND4L with bound lipids directly from nanodiscs

  • Identify specific lipid binding sites and preferences

  • Quantify binding affinities for different lipid species

• Molecular Dynamics Simulations:

  • Model MT-ND4L in various lipid compositions

  • Predict lipid binding sites and protein conformational changes

  • Calculate energetics of protein-lipid interactions

• Fluorescence-Based Approaches:

  • Förster resonance energy transfer (FRET) between labeled protein and lipids

  • Fluorescence recovery after photobleaching (FRAP) to measure diffusion in membranes

  • Environment-sensitive fluorophores to detect conformational changes

• Lipid Exchange Assays:

  • Measure rates of lipid exchange between MT-ND4L and surrounding membrane

  • Identify specifically retained lipids that resist exchange

  • Compare exchange rates across different MT-ND4L variants

• Atomic Force Microscopy:

  • Visualize MT-ND4L organization in model membranes

  • Measure mechanical properties of protein-lipid assemblies

  • Track protein clustering behavior in different lipid environments

• Reconstitution Studies:

  • Systematic variation of lipid composition in proteoliposomes

  • Measure functional parameters (electron transfer, proton pumping)

  • Identify optimal lipid environment for MT-ND4L function

• Chemical Crosslinking:

  • Use lipid-protein crosslinkers to capture transient interactions

  • Map interaction sites by mass spectrometry

  • Compare crosslinking patterns across species

These approaches can reveal how the lipid environment modulates MT-ND4L function and how this may differ between Atlantic walrus and other mammals, potentially reflecting adaptations to marine environments .

What techniques can be used to study the co-translational insertion and assembly of MT-ND4L into the inner mitochondrial membrane?

Studying the co-translational insertion and assembly of MT-ND4L into the inner mitochondrial membrane requires specialized techniques to capture this dynamic process:

• Ribosome Profiling with Mitochondrial Focus:

  • Selective isolation of mitochondrial ribosomes

  • Next-generation sequencing of ribosome-protected mRNA fragments

  • Analysis of translation kinetics and pausing sites specific to MT-ND4L

• In Organello Translation Assays:

  • Isolated mitochondria with radioactively labeled amino acids

  • Pulse-chase experiments to track nascent MT-ND4L synthesis and membrane insertion

  • Analysis of assembly intermediates using blue native PAGE

• Proximity Labeling During Translation:

  • APEX2 or BioID fused to mitochondrial ribosomal proteins

  • Temporal control of labeling to capture insertion machinery interactions

  • Mass spectrometry identification of proteins involved in MT-ND4L insertion

• Fluorescence Microscopy of Translation and Assembly:

  • CRISPR tagging of endogenous MT-ND4L with split fluorescent proteins

  • Live-cell imaging of synthesis, insertion, and assembly

  • Correlative light and electron microscopy for ultrastructural context

• Crosslinking Mass Spectrometry During Biogenesis:

  • Time-resolved crosslinking to capture transient interactions

  • Identification of assembly factors specific to MT-ND4L

  • Mapping the assembly pathway from translation to mature Complex I

• In Vitro Reconstitution Systems:

  • Cell-free translation systems with added mitochondrial membranes

  • Reconstitution of insertion machinery components

  • Systematic analysis of factors required for proper MT-ND4L insertion

• Genetic Approaches:

  • Conditional depletion of suspected assembly factors

  • Analysis of MT-ND4L insertion and Complex I assembly under depletion conditions

  • Rescue experiments with complementary factors from different species