Recombinant Archaeoglobus fulgidus Uncharacterized protein AF_2130 (AF_2130)

What is Archaeoglobus fulgidus AF_2130 protein?

AF_2130 is an uncharacterized protein from the hyperthermophilic archaeon Archaeoglobus fulgidus with the UniProt ID O28150. It is a small protein consisting of 99 amino acids with predicted membrane-associated properties. A. fulgidus is a sulfate-reducing archaeon that grows optimally at 83°C and can be found in high-temperature, high-pressure marine environments, typically 2-5 km below sea level at pressures of 20-50 MPa . The organism serves as a model extremophile for studying adaptations to extreme conditions, making its proteins particularly interesting for understanding molecular mechanisms of thermostability and pressure resistance .

How is recombinant AF_2130 typically produced for research applications?

Recombinant AF_2130 is produced in E. coli expression systems as indicated in commercial source information . The typical production process involves:

• Cloning the AF_2130 gene (1-99 amino acids) into an expression vector with an N-terminal His-tag

• Transformation into E. coli expression strains

• Induction of protein expression under controlled conditions

• Cell lysis and protein extraction

• Purification via immobilized metal affinity chromatography (IMAC)

• Further purification steps as needed

• Final preparation as a lyophilized powder

The commercially available recombinant protein is described as having greater than 90% purity as determined by SDS-PAGE . For research applications, the protein is typically reconstituted in deionized sterile water to a concentration of 0.1-1.0 mg/mL, with recommended addition of 5-50% glycerol for long-term storage .

What are the optimal storage and handling conditions for recombinant AF_2130?

Based on the extremophilic origin of AF_2130 and commercial product information, the following conditions are recommended:

When planning experiments, researchers should consider that A. fulgidus thrives at 83°C, so AF_2130 likely exhibits optimal stability and potential activity at elevated temperatures . For functional studies, temperature ranges of 60-95°C might be appropriate to mimic the natural growth conditions of the source organism .

What purification strategies are most effective for His-tagged AF_2130?

Purification of His-tagged AF_2130 typically follows these steps:

• Immobilized Metal Affinity Chromatography (IMAC):

  • Ni-NTA or Co-NTA resins are commonly used

  • Binding buffer typically contains imidazole at low concentration

  • Elution with increasing imidazole concentration gradient

• For membrane proteins like AF_2130:

  • Membrane extraction using appropriate detergents

  • Detergent screening may be necessary to maintain native conformation

  • Consider nanodiscs or liposome reconstitution for functional studies

• Quality Control:

  • SDS-PAGE to confirm purity (>90% as specified)

  • Mass spectrometry for identity confirmation

  • Potential structural validation through circular dichroism

The specific detergent requirements for AF_2130 extraction and stabilization would need to be determined empirically, as the optimal conditions may differ from those of mesophilic membrane proteins due to A. fulgidus' adaptation to extreme conditions.

How can researchers verify the structural integrity of purified AF_2130?

Since AF_2130 is uncharacterized with unknown function, structural integrity verification is crucial:

• Electrophoretic Analysis:

  • SDS-PAGE to confirm molecular weight and purity

  • Native PAGE to assess oligomerization state

• Spectroscopic Methods:

  • Circular dichroism (CD) to verify secondary structure content

  • Fluorescence spectroscopy to assess tertiary structure (if applicable)

  • FTIR for secondary structure analysis, particularly useful for membrane proteins

• Thermal Stability Assessment:

  • Differential scanning calorimetry (DSC)

  • Thermal shift assays (TSA)

  • CD thermal melts

• Hydrodynamic Analysis:

  • Size exclusion chromatography to assess aggregation state

  • Dynamic light scattering to determine size distribution

  • Analytical ultracentrifugation for precise molecular weight and shape analysis

Since AF_2130 is from a hyperthermophile, thermal stability analysis is particularly important and may reveal unusual stability profiles compared to mesophilic proteins.

What computational approaches can predict potential functions of AF_2130?

Multiple computational approaches can help predict potential functions of uncharacterized proteins like AF_2130:

• Sequence-Based Analysis:

  • Homology searches using PSI-BLAST, HHpred, or HMMER

  • Protein family classification (Pfam, InterPro)

  • Transmembrane topology prediction (TMHMM, Phobius)

  • Signal peptide prediction

• Structure-Based Prediction:

  • 3D structure prediction using AlphaFold2 or I-TASSER

  • Structural homology to characterized proteins

  • Binding pocket and active site prediction

  • Molecular dynamics simulations under high temperature/pressure

• Genomic Context Analysis:

  • Examination of adjacent genes and potential operons

  • Co-expression patterns with characterized genes

  • Phylogenetic profiling across archaeal species

• Integrated Analysis:

  • Combining multiple prediction methods for consensus

  • Weighting predictions based on confidence scores

  • Developing testable hypotheses based on computational predictions

For AF_2130 specifically, its predicted membrane localization suggests potential roles in membrane stability, transport, signaling, or protein complex formation, particularly under the extreme conditions where A. fulgidus thrives.

How does the heat shock response in A. fulgidus regulate proteins like AF_2130?

While the search results don't specifically mention AF_2130 in relation to heat shock, understanding A. fulgidus' general heat shock response provides important context:

A comprehensive microarray study revealed that when A. fulgidus cells were shifted from 78°C to 89°C, approximately 14% of the genome showed differential expression . Specifically:

• 189 ORFs exhibited increased expression

• 161 ORFs showed decreased expression

One differentially expressed gene, AF1298 (designated HSR1), was found to bind to promoter elements of heat shock-induced genes, with a potential palindromic recognition motif (CTAAC-N5-GTTAG) . To determine if AF_2130 is regulated during heat shock, researchers could:

• Analyze existing microarray data for AF_2130 expression patterns

• Perform RT-qPCR to quantify AF_2130 expression under heat shock

• Examine the AF_2130 promoter for potential HSR1 binding sites

• Use chromatin immunoprecipitation to identify regulatory proteins binding to the AF_2130 promoter

If AF_2130 is upregulated during heat shock, this would suggest a potential role in stress response or adaptation to temperature fluctuations.

How might high hydrostatic pressure affect the structure and function of AF_2130?

A. fulgidus has been shown to grow under high hydrostatic pressure (HHP) conditions up to 60 MPa, with maximum growth rates at 20 MPa for heterotrophic metabolism, suggesting it is a moderate piezophile . This has important implications for proteins like AF_2130:

• Structural Considerations:

  • Membrane proteins from piezophiles often have adaptations to maintain functionality under pressure

  • Pressure affects protein volume, hydration, and packing density

  • Conformational equilibria can shift under pressure

• Membrane Dynamics:

  • High pressure increases membrane rigidity, which may affect membrane protein function

  • Proteins like AF_2130 may have evolved structural features to accommodate pressure-induced membrane changes

  • Lateral pressure profiles within membranes change under pressure

• Experimental Approaches:

  • High-pressure biophysical techniques (HP-FTIR, HP-fluorescence) to study conformational changes

  • Reconstitution into liposomes of varying composition to study membrane-protein interactions

  • Molecular dynamics simulations to model pressure effects on structure

• Functional Implications:

  • Different A. fulgidus metabolic pathways show different optimal pressures

  • AF_2130 function may be pressure-dependent if involved in specific pressure-sensitive pathways

  • Protein-protein interactions may be altered under pressure

Understanding the pressure adaptations of proteins like AF_2130 requires specialized high-pressure equipment to maintain realistic environmental conditions during experiments.

What are key methodological considerations when expressing hyperthermophilic membrane proteins like AF_2130?

Expressing membrane proteins from hyperthermophiles presents multiple challenges:

For AF_2130 specifically:

• Consider its predicted membrane association when designing extraction and purification protocols

• Screen multiple detergents for optimal solubilization

• Test expression at different temperatures to balance protein production with proper folding

• Consider archaeal lipid mimetics for reconstitution experiments

The commercially available recombinant AF_2130 is expressed in E. coli with an N-terminal His-tag , demonstrating that successful heterologous expression is achievable despite these challenges.

What approaches can determine if AF_2130 interacts with other proteins or cellular components?

Given that AF_2130 is uncharacterized, systematic interaction studies are valuable:

• In vitro Interaction Assays:

  • Pull-down assays using His-tagged AF_2130 as bait

  • Surface plasmon resonance (SPR) with immobilized AF_2130

  • Isothermal titration calorimetry (ITC) for quantitative binding parameters

  • Liposome binding assays to test membrane interactions

• In vivo Approaches:

  • Bacterial two-hybrid systems adapted for high temperature

  • Protein complementation assays

  • In vivo crosslinking followed by mass spectrometry

  • Co-immunoprecipitation from A. fulgidus lysates

• Specialized Membrane Protein Methods:

  • Reconstitution into nanodiscs with potential partners

  • Lipid binding assays to identify specific lipid interactions

  • Blue native PAGE to identify native complexes

• Computational Predictions:

  • Protein-protein interaction databases

  • Structural docking simulations

  • Co-expression analysis across conditions

Interaction studies should consider the extreme conditions where A. fulgidus thrives, potentially including elevated temperature and pressure to capture physiologically relevant interactions .

How can researchers design experiments to identify the cellular function of AF_2130?

A systematic approach to elucidate AF_2130's function could include:

• Differential Expression Analysis:

  • Transcriptomics/proteomics under various stress conditions

  • Growth phase-dependent expression

  • Expression under different pressure and temperature regimes

• Genetic Approaches:

  • Gene deletion or knockdown (if genetic tools exist for A. fulgidus)

  • Heterologous expression and complementation studies

  • Overexpression phenotype analysis

• Localization Studies:

  • Immunolocalization with anti-AF_2130 antibodies

  • Membrane fractionation and protein detection

  • Fluorescent protein fusions (if feasible in A. fulgidus)

• Structural Studies:

  • X-ray crystallography or cryo-EM

  • NMR of soluble domains

  • Hydrogen-deuterium exchange mass spectrometry

• High-Throughput Screening:

  • Activity-based protein profiling

  • Ligand binding screens

  • Chemical genetic approaches

Given A. fulgidus' extremophilic nature, experiments should ideally mimic native conditions, including high temperature (83°C) and potentially high pressure (20-40 MPa) .

How might studying AF_2130 contribute to understanding extremophile adaptation mechanisms?

As an uncharacterized protein from a hyperthermophilic, piezotolerant organism, AF_2130 presents opportunities to explore fundamental adaptation mechanisms:

• Membrane Adaptations:

  • The predicted membrane association of AF_2130 may reveal specialized mechanisms for maintaining membrane integrity under extreme conditions

  • Could provide insights into lipid-protein interactions in extremophiles

  • May reveal novel membrane stabilization strategies

• Evolutionary Insights:

  • Comparative analysis with homologs from other extremophiles and mesophiles

  • Identification of conserved features essential for extremophilic adaptations

  • Understanding of convergent evolution in extreme environments

• Structure-Function Relationships:

  • Identification of specific structural features that confer thermostability

  • Understanding how proteins maintain functionality under combined high temperature and pressure

  • Insights into protein folding and stability in extreme conditions

• Biotechnological Applications:

  • Design principles for engineering thermostable and barostable proteins

  • Development of robust biocatalysts for industrial applications

  • Biomimetic approaches inspired by extremophilic adaptations

These studies align with ongoing research on A. fulgidus as a model organism for understanding life in extreme environments .

What methodological advances are needed to better study proteins from extremophiles like A. fulgidus?

Current limitations and needed advancements include:

• High-Pressure, High-Temperature Equipment:

  • Development of accessible high-pressure bioreactors for routine cultivation

  • High-pressure spectroscopic and structural biology tools

  • Combined high-pressure, high-temperature enzymatic assay platforms

• Genetic System Development:

  • Improved genetic manipulation tools for A. fulgidus

  • CRISPR-based technologies adapted for extremophiles

  • Reporter systems functional at high temperatures

• Membrane Mimetics:

  • Better archaeal lipid mimetics for membrane protein studies

  • Pressure-resistant membrane models

  • Archaeal-specific nanodiscs or proteoliposomes

• Computational Tools:

  • Specialized algorithms for extremophile protein prediction

  • Molecular dynamics force fields optimized for extreme conditions

  • Integration of pressure parameters in structural prediction tools

• In situ Analysis:

  • Technologies for studying proteins in their native high-pressure, high-temperature environments

  • Non-destructive imaging and analytical techniques for extremophiles

  • Real-time monitoring of protein behavior under extreme conditions

A. fulgidus research demonstrates the importance of high-pressure cultivation to better reflect in situ physiological conditions , highlighting the need for specialized equipment and approaches when studying extremophilic proteins.

How do membrane proteins from A. fulgidus compare with those from other extremophiles?

Comparative analysis of membrane proteins across extremophiles reveals important adaptations:

While specific information about AF_2130 in this comparative context is limited, its membrane protein characteristics make it an interesting candidate for studying such adaptations in extremophiles.

What are the most promising approaches for characterizing AF_2130 function?

Based on current knowledge, the most promising research directions include:

• Structural Characterization:

  • Determine high-resolution structure through crystallography or cryo-EM

  • Map membrane topology using accessibility labeling

  • Perform molecular dynamics simulations under varying temperature and pressure

• Expression Pattern Analysis:

  • Examine AF_2130 expression under various stress conditions, including heat shock

  • Compare expression patterns with known stress-response genes

  • Determine if expression is regulated by HSR1 or similar transcription factors

• Interaction Mapping:

  • Identify protein interaction partners through pull-down experiments

  • Characterize lipid binding preferences

  • Determine if AF_2130 forms part of larger membrane complexes

• Functional Screening:

  • Test for phenotypes under gene deletion/silencing (if genetic system available)

  • Screen for activity changes under varying pressure conditions

  • Examine response to membrane stress conditions

These approaches should ideally be conducted under conditions that mimic the extreme environment where A. fulgidus naturally thrives, including high temperature (83°C) and relevant pressure conditions (20-40 MPa) .