Recombinant Photobacterium profundum Selenide, water dikinase (selD)

What is selenide, water dikinase (selD) and what reaction does it catalyze?

Selenide, water dikinase (EC 2.7.9.3), also known as selenophosphate synthetase, is an enzyme that catalyzes the following chemical reaction:

ATP + selenide + H₂O → AMP + selenophosphate + phosphate

This reaction requires three substrates (ATP, selenide, and water) and produces three products (AMP, selenophosphate, and phosphate). The enzyme belongs to the transferase family, specifically phosphotransferases with paired acceptors (dikinases). The systematic name for this enzyme class is ATP:selenide, water phosphotransferase. It plays a critical role in selenoamino acid metabolism pathways in various organisms .

The reaction mechanism involves the transfer of phosphate groups from ATP, ultimately producing selenophosphate, which serves as the activated selenium donor for the biosynthesis of selenocysteine and other selenocompounds essential for selenium metabolism.

Why is Photobacterium profundum an interesting organism for studying selenide, water dikinase?

Photobacterium profundum, particularly the SS9 strain, represents a unique model system for studying enzyme function under extreme conditions. As a deep-sea bacterium adapted to high-pressure environments (barophilic organism), P. profundum has evolved molecular mechanisms to maintain enzymatic activity and protein stability under conditions that would typically denature proteins from surface-dwelling organisms .

The selD enzyme from P. profundum likely contains structural adaptations that enable function under high hydrostatic pressure conditions. This makes it particularly valuable for:

• Understanding pressure adaptations in enzyme catalysis

• Studying the evolution of extremophile metabolism

• Exploring the mechanistic relationship between pressure and selenium metabolism

• Developing biotechnological applications requiring pressure-stable enzymes

Additionally, P. profundum has been studied for its ability to grow under high-pressure conditions, with genomic libraries and mutant screens revealing important insights into pressure-adapted cellular processes, potentially including selenium metabolism .

What are the optimal conditions for expressing recombinant P. profundum selD in heterologous systems?

When expressing recombinant P. profundum selD in heterologous systems, researchers should consider several factors to optimize expression:

Expression System Selection:

• E. coli-based expression systems are commonly used, but care must be taken as the introduction of foreign genes like selD from P. profundum can have dramatic effects on host physiology, particularly under pressure conditions .

• Consider pressure-adapted expression systems for maintaining native enzyme conformations.

Culture Conditions:

• Temperature: Generally lower than standard (15-20°C) to mimic deep-sea conditions

• Pressure: Consider using specialized high-pressure bioreactors for expression

• Media composition: Include selenium supplementation (typically as sodium selenite)

• Induction parameters: Lower IPTG concentrations and longer induction times

Expression Optimization Table:

Purification Considerations:

• Include reducing agents in buffers to maintain selenide groups

• Consider pressure effects on protein folding and activity

• Implement rapid purification protocols to minimize oxidation

Researchers should validate expression through activity assays specific to selenophosphate synthetase rather than relying solely on SDS-PAGE visualization .

How can researchers accurately measure selenide, water dikinase activity in laboratory settings?

Measuring selenide, water dikinase activity presents several methodological challenges due to the reactive nature of the substrates and products. The following approaches can be implemented:

Direct Activity Assays:

• Coupled Enzyme Assays - Monitor AMP production through coupled enzyme reactions

• Selenophosphate Quantification - Measure selenophosphate formation using:

  • Atomic absorption spectroscopy with hydride generation

  • ICP-MS for selenium detection

  • 31P-NMR spectroscopy for phosphate transfer

Indirect Assessment Methods:

• Selenium Volatilization Assays - Similar to those used for bacterial isolates in selenium bioremediation studies:

  • Use gas trapping in alkaline peroxide solutions

  • Quantify trapped selenium by atomic absorption hydride-generation spectroscopy

  • Calculate rates normalized to protein content (μg Se g protein⁻¹ h⁻¹)

Activity Measurement Protocol:

• Prepare reaction mixture containing ATP, selenide, and appropriate buffers

• Initiate reaction by adding purified enzyme

• Incubate at desired temperature and pressure conditions

• Terminate reaction at specific time points

• Quantify products using techniques mentioned above

Key Considerations:

• Maintain anaerobic conditions to prevent selenide oxidation

• Include appropriate controls for non-enzymatic reactions

• Account for pressure effects on reaction kinetics when relevant

• Standard curves should be prepared under identical conditions

What experimental approaches are suitable for studying selD function under high-pressure conditions?

Investigating selD function under high-pressure conditions requires specialized equipment and methodologies:

High-Pressure Experimental Systems:

• Pressure Bioreactors - For whole-cell studies of recombinant systems

• High-Pressure Stopped-Flow Devices - For rapid kinetic measurements

• Diamond Anvil Cells - For spectroscopic studies under extreme pressure

Experimental Approaches:

• Comparative Analysis - Compare selD activity from P. profundum with homologs from non-barophilic organisms under varying pressures.

• Mutational Studies - Identify pressure-adaptive residues through site-directed mutagenesis and activity assays.

• Structural Biology - Use high-pressure X-ray crystallography or NMR to determine structural changes under pressure.

Pressure-Effect Investigation Protocol:

• Establish baseline activity at atmospheric pressure

• Measure activity across a pressure gradient (e.g., 1, 100, 200, 280 atm)

• Determine pressure stability by pre-incubating enzyme at high pressure before activity measurements

• Assess reversibility by returning to atmospheric pressure and re-measuring activity

Control Considerations:

• Include pressure-sensitive and pressure-resistant control enzymes

• Account for pressure effects on pH and substrate solubility

• Design equipment that allows sampling without decompression when possible

Researchers should note that P. profundum growth is pressure-dependent, with some strains showing altered growth characteristics at elevated pressures (280 atm). Similar methodologies used in the study of RecD function under high pressure can be adapted for selD research .

How does selD from P. profundum contribute to selenium metabolism in deep-sea environments?

The role of selenide, water dikinase (selD) in P. profundum reflects important adaptations for selenium utilization in the deep sea:

Ecological Significance:

• Deep-sea environments may contain varying levels of selenium, and efficient selenium metabolism would provide selective advantages.

• The ability to produce selenophosphate is essential for incorporating selenium into proteins as selenocysteine.

• High-pressure adaptations of selD likely ensure continued function in the deep-sea habitat.

Metabolic Pathway Integration:

• SelD catalyzes a key step in selenium assimilation, converting selenide to selenophosphate.

• Selenophosphate serves as an activated selenium donor for selenocysteine incorporation.

• This pathway connects to broader aspects of cell metabolism, including:

  • Redox homeostasis

  • Protection against oxidative stress

  • Energy metabolism through selenoprotein function

Barophilic Adaptations:

• Structural features likely allow the enzyme to maintain appropriate conformational flexibility under high pressure.

• Possible coordination with other pressure-adapted cellular components, similar to the RecD system which shows pressure-dependent function in P. profundum .

Research Implications:

• Understanding selD function in deep-sea bacteria provides insights into selenium biogeochemical cycling in marine environments.

• The enzyme may have evolved unique catalytic properties optimized for high-pressure conditions.

• Comparative studies with surface-dwelling organisms could reveal molecular mechanisms of pressure adaptation in enzyme catalysis.

What role might selD play in potential selenium bioremediation applications using extremophiles?

The potential application of selD-containing extremophiles like P. profundum in selenium bioremediation presents an intriguing research direction:

Bioremediation Context:

• Selenium contamination is a significant environmental concern, particularly in agricultural drainage water and certain industrial effluents.

• Biological volatilization of selenium compounds represents a promising bioremediation approach, converting toxic selenate to less harmful volatile forms .

Extremophile Advantages:

• P. profundum, as a barophilic organism with selenide, water dikinase activity, could potentially be engineered for enhanced selenium processing.

• Extremophiles often show superior tolerance to toxic conditions, making them candidates for bioremediation of challenging environments.

• The ability to function under extreme conditions (high pressure, variable salinity) could expand the range of treatable environments.

Comparative Performance Metrics:
Comparing P. profundum with established selenium-volatilizing bacteria:

Research Directions:

• Engineer recombinant P. profundum with enhanced selD expression

• Test selenium volatilization rates under various environmental conditions

• Develop bioreactors capable of maintaining optimal conditions for selenium processing

• Evaluate the ecological safety of engineered strains in potential release scenarios

The special adaptation of P. profundum to high-pressure environments may provide unique advantages for specialized bioremediation applications where traditional approaches are insufficient .

How do mutations in selD affect selenium metabolism and pressure adaptation in P. profundum?

Understanding the relationship between selD mutations and phenotypes in P. profundum provides insights into both selenium metabolism and pressure adaptation:

Mutation Impact Analysis:

• Similar to RecD mutations that affect high-pressure growth in P. profundum, selD mutations likely impact both selenoprotein synthesis and possibly pressure adaptation .

• Point mutations creating premature stop codons would truncate the protein and potentially eliminate enzymatic activity.

• Mutations affecting the active site would impact catalytic efficiency while potentially preserving structural integrity.

Phenotypic Consequences:

• Selenium Metabolism Defects:

  • Reduced selenophosphate production

  • Impaired selenoprotein synthesis

  • Altered selenium tolerance profiles

• Pressure-Related Phenotypes:

  • Potentially altered growth rates under high pressure

  • Changes in cell morphology or membrane characteristics

  • Modification of gene expression patterns under pressure

Experimental Approach for Mutation Studies:

• Generate selD mutants through:

  • Targeted gene disruption

  • Point mutations at conserved residues

  • 3' truncations of varying lengths

• Characterize mutants through:

  • Growth curves at various pressures (1 atm vs. 280 atm)

  • Selenoprotein profiling

  • Selenium tolerance testing

  • Complementation studies with wild-type selD

Complementation Analysis:
Similar to studies with RecD in P. profundum, complementation tests with selD would be valuable:

• Delivering wild-type selD into mutant strains should restore selenophosphate synthetase activity

• The degree of phenotypic rescue may depend on the nature and location of the original mutation

• Introduction of P. profundum selD into E. coli selD mutants could reveal pressure-adaptive properties of the enzyme

What statistical approaches are most appropriate for analyzing selD activity data under variable pressure conditions?

When analyzing selD activity data under variable pressure conditions, researchers should employ robust statistical approaches that account for the unique challenges of pressure biology research:

Recommended Statistical Frameworks:

• Repeated Measures ANOVA with pressure as the within-subject factor

  • Appropriate for tracking activity changes across multiple pressure points

  • Can incorporate additional factors such as temperature or pH

  • Post-hoc tests (e.g., Tukey's HSD) to identify significant pressure thresholds

• Non-Linear Regression Models for pressure-activity relationships

  • Fit pressure-response curves to identify:

    • Optimal pressure for activity (Popt)

    • Pressure range tolerance (ΔP50)

    • Pressure inactivation constants

• Mixed-Effects Models for complex experimental designs

  • Accommodate random effects from batches or biological replicates

  • Handle missing data points common in high-pressure experimentation

  • Appropriate for longitudinal pressure studies

Data Normalization Considerations:

• Normalize activity to protein concentration

• Consider pressure effects on assay components and adjust baseline accordingly

• Apply appropriate transformations (log, square root) to meet statistical assumptions

Statistical Visualization Approaches:

• Pressure-activity profiles with confidence intervals

• 3D surface plots for multi-factor experiments (pressure × temperature × pH)

• Forest plots for comparing pressure effects across different selD variants

Sample Size and Power Analysis:

• Conduct a priori power analysis specific to pressure biology experiments

• Account for typically higher variability in high-pressure measurements

• Consider sequential analysis approaches to optimize resource-intensive pressure experiments

These statistical approaches should be implemented with careful consideration of the experimental design used in single-case experimental designs (SCEDs) when working with limited biological samples .

How can researchers reconcile contradictory data from in vitro and in vivo studies of recombinant selD function?

Reconciling contradictions between in vitro and in vivo studies of recombinant selD requires systematic analysis of potential sources of discrepancy:

Common Sources of Discrepancy:

• Environmental Context Differences

  • In vitro: Isolated enzyme in defined buffer

  • In vivo: Complex cellular environment with multiple interacting systems

  • Resolution approach: Develop intermediate complexity systems (e.g., cell extracts, reconstituted systems)

• Pressure-Dependent Protein-Protein Interactions

  • selD may interact with different partners under varying pressure conditions

  • These interactions may be disrupted in purified systems

  • Resolution approach: Co-purification and activity assays with potential interaction partners

• Post-Translational Modifications

  • Different modification patterns between expression systems

  • Pressure-induced modification changes

  • Resolution approach: Comprehensive proteomic analysis of native and recombinant selD

Reconciliation Framework:

Integration Strategies:

• Systems Biology Approach

  • Develop mathematical models integrating both datasets

  • Identify missing components explaining discrepancies

  • Design targeted experiments to test model predictions

• Iterative Refinement Protocol

  • Begin with simplest in vitro conditions

  • Gradually increase system complexity toward in vivo conditions

  • Identify transition points where discrepancies emerge

• Multimodal Validation

  • Complement activity data with structural information

  • Correlate protein dynamics with function under pressure

  • Use genetic approaches to validate biochemical findings

This reconciliation process should incorporate principles from experimental design in systems biology, where dynamic behavior analysis and careful stimulation-observation pairing are essential .

What are the best practices for comparing selD function across different pressure-adapted bacterial species?

Conducting cross-species comparisons of selD function in pressure-adapted bacteria requires careful methodological considerations:

Experimental Design Principles:

• Phylogenetically Informed Sampling

  • Include barophilic, barotolerant, and pressure-sensitive species

  • Consider evolutionary relationships when interpreting functional differences

  • Include multiple strains within each species to account for strain variation

• Standardized Functional Assays

  • Develop consistent protocols applicable across species

  • Account for optimal growth conditions of each organism

  • Normalize activity to appropriate reference parameters

• Comparative Expression Systems

  • Express selD genes from different species in the same host

  • Create chimeric proteins to identify pressure-adaptive domains

  • Evaluate performance across a pressure gradient

Key Analysis Approaches:

• Structure-Function Correlation

  • Align selD sequences across pressure-adapted species

  • Identify amino acid substitutions in pressure-adapted variants

  • Correlate specific residues with pressure tolerance parameters

• Comparative Pressure Adaptation Metrics

  • P₅₀: Pressure at which 50% activity is retained

  • Pmax: Maximum pressure supporting activity

  • Recovery ratio: Activity recovery after pressure treatment

  • Volume change of activation (ΔV‡): Thermodynamic parameter of pressure sensitivity

Data Presentation Framework:

Integration with Genomic Approaches:

• Correlate selD sequence variations with genomic signatures of pressure adaptation

• Consider horizontal gene transfer events in evolutionary interpretation

• Examine synteny and operon structure across species

This comparative approach follows principles established in single-case experimental designs (SCEDs) research, allowing for meaningful cross-species comparisons even with limited sample availability .

What are the main technical challenges in generating stable recombinant P. profundum selD and how can they be overcome?

Researchers face several significant technical challenges when working with recombinant P. profundum selD:

Challenge 1: Plasmid Stability Issues

• P. profundum, like some RecD mutants, may exhibit plasmid stability issues

• Solution approaches:

  • Use low-copy number expression vectors

  • Employ integrative expression systems

  • Implement selection pressure throughout cultivation

  • Regularly verify plasmid retention through PCR

Challenge 2: Protein Solubility and Folding

• Extremophile proteins often misfold when expressed in mesophilic hosts

• Solution approaches:

  • Co-express molecular chaperones

  • Utilize fusion partners (MBP, SUMO) to enhance solubility

  • Express at lower temperatures (15-20°C)

  • Consider cell-free expression systems

Challenge 3: Selenium Toxicity

• Working with selenide can be toxic to expression hosts

• Solution approaches:

  • Use selenium-tolerant host strains

  • Implement tight expression control

  • Optimize selenium concentration in media

  • Consider inducible detoxification pathways

Challenge 4: Pressure Effects on Expression

• Standard expression systems operate at atmospheric pressure

• Solution approaches:

  • Develop pressure-adapted expression hosts

  • Utilize pressure bioreactors for expression

  • Employ post-expression pressure treatment

  • Design pressure-stable expression vectors

Challenge 5: Activity Preservation During Purification

• SelD enzyme activity can be lost during conventional purification

• Solution approaches:

  • Rapid purification protocols

  • Include stabilizing agents in buffers

  • Maintain reducing conditions throughout

  • Consider affinity purification under anaerobic conditions

Optimization Protocol:

• Begin with small-scale expression trials varying key parameters

• Implement DoE (Design of Experiments) approach to optimize conditions

• Develop activity-based screening methods to track functional protein

• Consider native purification from P. profundum as a reference standard

How can researchers effectively design mutagenesis studies to identify pressure-adaptive features of selD?

Designing effective mutagenesis studies to elucidate pressure-adaptive features of selD requires a strategic approach:

Mutagenesis Strategy Framework:

• Sequence-Based Targeting

  • Compare selD sequences across barophilic and non-barophilic organisms

  • Identify residues unique to pressure-adapted variants

  • Create point mutations converting "pressure-adapted" residues to "surface-type" residues

  • Focus on:

    • Charged amino acid distributions

    • Flexibility-conferring regions

    • Hydrogen bonding networks

• Structure-Guided Approach

  • Model P. profundum selD structure using homology modeling

  • Identify cavities that may be affected by pressure

  • Target residues involved in conformational flexibility

  • Focus on regions showing pressure-dependent movements

• Systematic Domain Swapping

  • Create chimeric proteins combining domains from pressure-adapted and non-adapted selD

  • Evaluate pressure tolerance of each chimera

  • Narrow down to smaller regions and eventually specific residues

Experimental Validation Hierarchy:

Evaluation Framework:

• Assay enzymatic activity across pressure gradients (1-500 atm)

• Determine pressure stability profiles for each variant

• Measure thermodynamic parameters (ΔV‡) for pressure-sensitive steps

• Correlate structural features with functional outcomes

This mutagenesis strategy incorporates principles from research on RecD function in P. profundum, where specific mutations affected high-pressure growth phenotypes .

What considerations are important when designing high-pressure experiments to study recombinant selD kinetics?

Designing high-pressure experiments for studying recombinant selD kinetics requires attention to several specialized considerations:

Equipment Selection and Validation:

• Pressure Generation Systems

  • Hydraulic pressure generators for biochemical studies

  • Gas compression systems for whole-cell studies

  • Diamond anvil cells for spectroscopic investigations

• Reaction Vessel Requirements

  • Material compatibility with high pressure

  • Optical access for real-time measurements

  • Temperature control integration

  • Sample introduction without depressurization

Experimental Design Parameters:

• Pressure Range Determination

  • Include native habitat pressure (280 atm for P. profundum)

  • Extend beyond natural range to determine limits

  • Use logarithmic pressure increments for efficient sampling

• Time-Resolved Measurements

  • Plan sampling intervals appropriate for reaction kinetics

  • Consider pressure equilibration times

  • Account for potential pressure effects on reaction rates

Critical Control Measures:

• System Calibration

  • Use pressure-sensitive fluorophores to verify actual sample pressure

  • Include internal pressure standards

  • Verify pressure homogeneity throughout reaction vessel

• Buffer Considerations

  • Account for pressure effects on pH (typically 0.014 pH units/100 atm)

  • Consider pressure effects on ionization equilibria

  • Use pressure-insensitive buffer systems when possible

Data Collection Optimization:

Technical Challenges and Solutions:

• Challenge: Pressure effects on assay components
  Solution: Determine pressure effects on each component independently

• Challenge: Limited sample volume in pressure vessels
  Solution: Miniaturize assays and utilize high-sensitivity detection

• Challenge: Maintaining pressure during measurements
  Solution: Develop in situ measurement capabilities

These considerations align with established practices in high-pressure biochemistry and build upon methodologies used for studying pressure-adapted systems like those in P. profundum .

What emerging technologies might advance our understanding of selD function in extremophiles?

Several cutting-edge technologies are poised to revolutionize our understanding of selD function in extremophiles like P. profundum:

Advanced Structural Biology Approaches:

• Cryo-Electron Microscopy Under Pressure

  • Capturing selD structures in near-native pressure environments

  • Visualizing pressure-induced conformational changes

  • Resolving dynamic structural ensembles

• Time-Resolved X-ray Crystallography

  • Capturing catalytic intermediates of selD

  • Pressure-jump experiments to trigger conformational changes

  • Mapping the energy landscape of pressure adaptation

• High-Pressure NMR Spectroscopy

  • Monitoring protein dynamics under variable pressure

  • Mapping pressure-dependent hydrogen bonding networks

  • Characterizing millisecond-timescale motions relevant to catalysis

Genomic and Systems Biology Technologies:

• Single-Cell Transcriptomics Under Pressure

  • Revealing pressure-dependent expression patterns

  • Identifying co-regulated genes in selenium metabolism

  • Mapping regulatory networks involving selD

• CRISPR-Cas9 Engineering of Barophiles

  • Precise genome editing of P. profundum

  • Creating selD variant libraries in native contexts

  • High-throughput phenotyping under pressure

Computational and Simulation Approaches:

• Molecular Dynamics at Variable Pressure

  • Simulating selD behavior across pressure gradients

  • Identifying water penetration and cavity changes

  • Calculating energetics of pressure adaptation

• Machine Learning for Pressure Adaptation Prediction

  • Training on known pressure-adapted enzymes

  • Predicting critical residues for pressure tolerance

  • Designing novel pressure-adapted selD variants

Enabling Technologies Table:

These emerging technologies will enable researchers to move beyond the current limitations in studying pressure-adapted enzymes like selD in P. profundum, potentially leading to breakthroughs in understanding extreme environment adaptation mechanisms.

How might comparative genomics of deep-sea bacteria advance our understanding of pressure-adapted selD variants?

Comparative genomics offers powerful approaches for understanding pressure-adapted selD variants in deep-sea bacteria:

Genomic Comparison Frameworks:

• Phylogenomic Analysis

  • Construct selD phylogenetic trees across marine depth gradients

  • Identify convergent evolution patterns in pressure-adapted lineages

  • Correlate selD sequence variations with habitat depth

• Synteny and Operon Structure Analysis

  • Compare genomic context of selD across pressure-adapted species

  • Identify co-evolved genes that may function with selD under pressure

  • Analyze regulatory elements controlling selD expression

• Horizontal Gene Transfer Assessment

  • Investigate potential HGT events of selD between barophiles

  • Identify mobile genetic elements associated with pressure-adapted selD variants

  • Analyze codon usage patterns to detect recent transfer events

Sequence-Structure-Function Correlations:

Integration with Experimental Data:

• Connect genomic features with experimental pressure tolerance data

• Validate computational predictions through targeted mutagenesis

• Develop predictive models of selD pressure adaptation

Implementation Strategy:

• Create a comprehensive database of selD sequences from marine bacteria across depth gradients

• Develop specialized bioinformatic pipelines for pressure adaptation analysis

• Correlate genomic features with habitat depth and measured pressure tolerance

• Generate testable hypotheses about critical pressure-adaptive features

This comparative genomics approach would build upon knowledge gained from studies of pressure-adapted proteins in organisms like P. profundum, where specific genes have been identified as critical for high-pressure growth .

What potential biotechnological applications might emerge from studying pressure-adapted selD enzymes?

Research on pressure-adapted selD enzymes from organisms like P. profundum presents several promising biotechnological applications:

Biocatalysis Under Extreme Conditions:

• High-Pressure Enzymatic Processes

  • Leverage pressure-adapted selD for reactions requiring high pressure

  • Develop biocatalytic processes with improved thermodynamics under pressure

  • Create enzyme cascades functioning in deep-sea conditions

• Selenium Biotransformation

  • Engineer pressure-adapted selD for improved selenium bioconversion

  • Develop processes for pharmaceutical-grade selenocompound production

  • Create robust systems for selenoprotein synthesis

Environmental Applications:

• Advanced Bioremediation Technologies

  • Develop engineered organisms with enhanced selenium detoxification

  • Create pressure-tolerant bioremediation systems for deep-sea contamination

  • Design selenium recovery systems for resource extraction

• Biosensors for Extreme Environments

  • Utilize selD-based systems to detect selenium in high-pressure environments

  • Develop pressure-stable biosensors for deep-sea monitoring

  • Create robust detection systems for environmental selenium speciation

Biomedical Applications:

• Therapeutic Selenoprotein Production

  • Utilize pressure-adapted selD for improved selenoprotein synthesis

  • Develop expression systems for difficult-to-produce selenoproteins

  • Create novel selenium-containing therapeutic compounds

• High-Pressure Protein Folding Assistance

  • Apply knowledge of pressure adaptation to protein folding problems

  • Develop pressure-cycling protocols for difficult protein refolding

  • Create pressure-tolerant chaperone systems

Comparison of Potential Applications:

Development Pathway:

• Fundamental characterization of pressure effects on selD

• Engineering optimized variants for specific applications

• Scale-up and integration into relevant technological processes

• Field testing in actual extreme environments

These applications represent the translational potential of basic research on extremophile enzymes like the selD from P. profundum, potentially creating new biotechnological capabilities for operating under extreme conditions .