Recombinant Synechococcus sp. Elongation factor Ts (tsf)

What is Elongation Factor Ts (tsf) in Synechococcus sp.?

Elongation factor Ts (EF-Ts) is a protein that functions in the translation elongation process in Synechococcus sp., a genus of photosynthetic cyanobacteria. This protein specifically facilitates the recycling of elongation factor Tu (EF-Tu) by promoting the exchange of GDP for GTP, thereby enabling continued protein synthesis. In Synechococcus sp., EF-Ts is particularly important as it indirectly contributes to photosynthetic processes and stress responses.

EF-Ts functions within a complex protein synthesis network where it works together with EF-Tu, which is crucial for the repair of photosystem II (PSII) . The protein has been characterized with the UniProt accession number Q3AXJ0 from Synechococcus sp. strain CC9902 .

How does Elongation Factor Ts interact with Elongation Factor Tu?

Elongation Factor Ts interacts with Elongation Factor Tu (EF-Tu) to facilitate the GDP-GTP exchange cycle essential for protein translation. When EF-Tu is bound to GDP, it adopts an open conformation that makes it less reactive to oxidation. The interaction between EF-Ts and EF-Tu triggers conformational changes in the switch I and II regions of EF-Tu, creating a tunnel that can expose key residues (like C82 in EF-Tu) to potential oxidation by reactive oxygen species .

This interaction is particularly significant in photosynthetic organisms like Synechococcus sp., where EF-Tu plays a critical role in the repair of photosystem II (PSII), which is highly susceptible to oxidative stress induced by light exposure. The regulatory function of EF-Ts in this process affects photosynthetic efficiency and stress responses .

What are the optimal storage conditions for recombinant Synechococcus sp. Elongation Factor Ts?

For optimal stability and activity of recombinant Synechococcus sp. Elongation factor Ts, specific storage conditions are recommended:

• Liquid formulations should be stored at -20°C/-80°C with an expected shelf life of approximately 6 months.

• Lyophilized formulations can be stored at -20°C/-80°C with an extended shelf life of up to 12 months.

• Working aliquots should be kept at 4°C for no more than one week to maintain activity.

• Repeated freeze-thaw cycles should be avoided to prevent protein degradation and loss of activity.

• For reconstitution, the protein should be dissolved in deionized sterile water to a concentration of 0.1-1.0 mg/mL, with the addition of 5-50% glycerol (final concentration) recommended for long-term storage .

What expression systems are suitable for producing recombinant Synechococcus sp. Elongation Factor Ts?

Based on available research, recombinant Synechococcus sp. Elongation factor Ts has been successfully expressed in yeast expression systems . This approach leverages the eukaryotic protein synthesis machinery to produce properly folded bacterial proteins.

For optimal expression, researchers should consider the following:

• The complete coding sequence (positions 1-219) should be included to ensure full functionality.

• Expression vectors may include various tag options, which would be determined during the manufacturing process based on purification requirements.

• Post-expression purification typically achieves >85% purity as assessed by SDS-PAGE analysis.

• The protein can be expressed with different tags depending on the experimental requirements, though the specific tag type would be determined during the manufacturing process .

How do reactive oxygen species (ROS) regulate Elongation Factor function in Synechococcus sp.?

Reactive oxygen species (ROS) play a significant regulatory role in modulating the function of elongation factors in Synechococcus sp., particularly affecting photosynthetic efficiency. Although the search results focus primarily on EF-Tu rather than EF-Ts, the mechanisms likely have implications for the EF-Ts/EF-Tu functional cycle.

This structural arrangement makes the closed conformation of EF-Tu vulnerable to oxidation, with C82 serving as a regulatory element governing photosynthetic biosynthesis. Mutation studies where C82 was substituted with serine (C82S) showed alleviation of photoinhibition, highlighting the role of this residue in EF-Tu photosensitivity .

This ROS-sensing mechanism likely influences the EF-Ts/EF-Tu cycle, as EF-Ts is responsible for facilitating the conformational changes in EF-Tu that expose the ROS-sensitive residues.

What genetic manipulation techniques are most effective for studying Elongation Factor Ts function in Synechococcus species?

Recent advances in genetic manipulation techniques for Synechococcus species provide powerful tools for studying Elongation Factor Ts function. A particularly promising approach is the development of markerless strain modification methods, which allow for multiple genetic modifications without the limitations imposed by antibiotic selection markers.

For Synechococcus sp. PCC 7002, a marine cyanobacterium similar to the strain containing the EF-Ts protein in question, researchers have developed a counter-selection system based on a mutated phenylalanyl-tRNA synthetase gene (pheS). This system introduces specific amino acid substitutions (T261A and A303G) in PheS that cause high susceptibility to the phenylalanine analog p-chlorophenylalanine (PCPA) .

The method involves:

• Temporary introduction of the mutated pheS gene into the genome

• Selection of transformants using PCPA resistance

• Markerless gene knockout or gene replacement

• Counter-selection with PCPA to remove the selection marker

This approach has been demonstrated for successful markerless knockout of genes (such as nblA) and for introducing foreign genes (such as lldD and lldP from E. coli) . The same technique could be applied to study EF-Ts function through:

• Creating precise deletions or mutations in the tsf gene

• Introducing modified versions of tsf to study structure-function relationships

• Developing reporter systems to monitor EF-Ts activity under various conditions

• Performing multiple sequential modifications to study EF-Ts interactions with other cellular components

What approaches can be used to study the role of Elongation Factor Ts in photosystem repair mechanisms?

Studying the role of Elongation Factor Ts in photosystem repair mechanisms requires specialized techniques that account for the complexities of photosynthetic processes. Based on the research on related elongation factors, several approaches can be implemented:

• Site-directed mutagenesis: Targeting specific residues in EF-Ts that interact with EF-Tu can help elucidate how these proteins cooperate in photosystem II repair. This approach has proven valuable in understanding how the C82S mutation in EF-Tu affects photoinhibition .

• Structural biology: X-ray crystallography at high resolution (1.7-2.0 Å) has been successful in revealing the conformational changes in EF-Tu associated with GDP/GTP binding and ROS sensitivity . Similar approaches could be applied to EF-Ts and EF-Ts/EF-Tu complexes.

• Controlled growth conditions: Utilizing specialized equipment like the MC-1000 multicultivator bioreactor allows for precise control of parameters such as temperature (38°C), light intensity (125-900 μmol photons m−2 s−1), and CO2 concentration (5%). These controlled conditions enable researchers to study photosystem repair mechanisms under varying levels of photoinhibition .

• Biomass quantification: Measuring changes in growth rates and biomass accumulation under different conditions can provide insights into the efficiency of photosystem repair mechanisms. Methods include spectrophotometric measurement at 750 nm and dry weight determination using microfiber filters .

• Development of vitamin B12-independent strains: For certain Synechococcus strains that require vitamin B12, developing independent strains through methods similar to those used for PCC 11901 can eliminate cultivation constraints and facilitate more comprehensive studies of translation factors under various conditions .

How can markerless strain development techniques be optimized for studying Elongation Factor Ts function?

Optimizing markerless strain development techniques for studying Elongation Factor Ts function requires careful consideration of several factors based on recent advancements in Synechococcus genetic manipulation:

• Selection of appropriate counter-selection markers: While the mutated pheS system has shown promise in Synechococcus sp. PCC 7002, other systems such as sacB and codA have shown variable effectiveness across different cyanobacterial species. For example, sacB works well in PCC 6803 but is ineffective in PCC 7002 . Testing multiple counter-selection systems is advisable when working with different Synechococcus strains.

• Optimization of marker sensitivity: For the pheS system, the optimal PCPA concentration was determined to be 20 μg/mL, with specific amino acid substitutions (T261A and A303G) providing the highest susceptibility . Similar optimization should be performed for any counter-selection system used.

• Incubation conditions for transformation: Various transformation protocols have shown different efficacies. For natural transformation in PCC 11901, protocols have included:

  • Mixing marked plasmids with cells for 4 or 24 hours in liquid media before plating

  • Incubation on agar plates for 24 hours followed by addition of antibiotic-containing agar

  • Multiple re-streaking to ensure complete segregation

• Verification of genetic modifications: PCR-based verification using primers that flank the deleted or modified regions is essential for confirming successful modifications .

• Strain-specific adaptations: Different Synechococcus strains may require specific growth media (such as AD7 or BG11) and antibiotic concentrations (e.g., 25 μg/mL spectinomycin, 50-100 μg/mL kanamycin) .

By optimizing these parameters, researchers can develop efficient markerless modification systems for introducing precise changes to the tsf gene or related genes, enabling detailed functional studies of Elongation Factor Ts.

What methodologies are recommended for assessing the quality and activity of recombinant Elongation Factor Ts?

To ensure the reliability of experiments involving recombinant Synechococcus sp. Elongation Factor Ts, comprehensive quality assessment is essential. Based on research practices for similar proteins, the following methodologies are recommended:

• Purity assessment:

  • SDS-PAGE analysis with a quality threshold of >85% purity

  • Densitometry analysis to quantify protein bands

  • Western blotting with specific antibodies to confirm identity

• Structural integrity verification:

  • Circular dichroism (CD) spectroscopy to assess secondary structure

  • Thermal shift assays to determine protein stability

  • Limited proteolysis to confirm proper folding

• Functional activity assays:

  • GDP/GTP exchange activity assays with purified EF-Tu

  • Fluorescence-based binding assays to measure EF-Tu interaction

  • Ribosome-binding assays to assess translation competence

• Storage stability monitoring:

  • Activity retention tests after storage under recommended conditions

  • Freeze-thaw stability assessment

  • Long-term activity measurements (over 6-12 months)

• Reconstitution protocol validation:

  • Activity comparison between different reconstitution methods

  • Optimization of protein concentration (0.1-1.0 mg/mL)

  • Assessment of different glycerol concentrations (5-50%) for storage

• Application-specific quality controls:

  • For photosynthesis studies: in vitro translation assays with chloroplast proteins

  • For stress response research: activity measurements under oxidative conditions

  • For structural studies: dynamic light scattering to assess homogeneity

These methodologies provide a comprehensive framework for ensuring that recombinant Elongation Factor Ts maintains its structural integrity and functional activity throughout experimental procedures.

How does the expression of Elongation Factor Ts vary under different growth conditions in Synechococcus sp.?

While the search results don't provide direct information on EF-Ts expression variation, insights can be drawn from studies on cyanobacterial growth conditions that likely affect translation factors. Synechococcus species show remarkable adaptability to different environmental conditions, with corresponding changes in protein expression patterns.

Growth conditions known to affect protein expression in Synechococcus species include:

• Light intensity: When cultured under varying light intensities (125-900 μmol photons m−2 s−1), Synechococcus species demonstrate adaptive changes in photosynthetic apparatus composition and repair mechanisms. Since EF-Tu (which interacts with EF-Ts) is involved in photosystem II repair, EF-Ts expression likely responds to light conditions .

• Temperature: Optimal growth for many Synechococcus strains occurs at 38°C, but temperature shifts can trigger stress responses that affect translation machinery components .

• Carbon dioxide concentration: Growth with elevated CO2 (5%) enhances photosynthetic efficiency and likely influences the expression of translation factors involved in synthesizing photosynthetic proteins .

• Nutrient availability: Strains like PCC 11901 show vitamin B12 auxotrophy, with corresponding adaptations in metabolism and protein synthesis when this nutrient is limited or absent .

• Oxidative stress: Since reactive oxygen species play a regulatory role in elongation factor function, oxidative stress conditions would likely trigger changes in EF-Ts expression and activity .

To study these variations, researchers can use:

• Quantitative PCR to measure tsf gene expression

• Proteomics approaches to quantify EF-Ts protein levels

• Reporter gene constructs fused to the tsf promoter to monitor expression in real-time

• Western blotting with specific antibodies against EF-Ts

What experimental protocols are recommended for studying the interaction between Elongation Factor Ts and other translation factors?

To effectively study interactions between Elongation Factor Ts and other translation components, particularly EF-Tu, several experimental protocols can be employed:

• Co-crystallization studies: X-ray crystallography at high resolution (1.7-2.0 Å) has successfully revealed structural details of EF-Tu in both wild-type and mutated forms . Similar approaches can be applied to EF-Ts alone and in complex with EF-Tu to understand binding interfaces and conformational changes.

• Site-directed mutagenesis: Systematic mutation of key residues in EF-Ts can help identify interaction sites with EF-Tu. For example, studies on EF-Tu showed how the C82S mutation affects its susceptibility to oxidation and photoinhibition .

• In vitro binding assays:

  • Surface plasmon resonance (SPR) to measure binding kinetics

  • Isothermal titration calorimetry (ITC) for thermodynamic parameters

  • Fluorescence anisotropy to detect complex formation

• Functional reconstitution assays:

  • GDP/GTP exchange assays with purified components

  • Ribosome-binding experiments to assess functional outcomes

  • Translation elongation rate measurements

• Crosslinking studies: Chemical crosslinking followed by mass spectrometry can identify specific residues involved in protein-protein interactions between EF-Ts and translation partners.

• Molecular dynamics simulations: Computational approaches can predict how EF-Ts conformational changes affect its interaction with EF-Tu and other factors, particularly under conditions mimicking oxidative stress.

• Genetic approaches:

  • Development of markerless strains with modified tsf genes

  • Creation of reporter systems to monitor interactions in vivo

  • Suppressor mutation screens to identify functional relationships

These protocols provide complementary approaches to understanding the complex relationships between EF-Ts and other components of the translation machinery in Synechococcus sp.

How can Elongation Factor Ts be utilized in biotechnology applications?

Elongation Factor Ts from Synechococcus sp. has several potential biotechnology applications, particularly in systems leveraging photosynthetic organisms:

• Enhancing recombinant protein production: Optimization of translation factors like EF-Ts could improve protein synthesis rates in cyanobacterial expression systems. This is particularly relevant as marine cyanobacteria like Synechococcus PCC 7002 are recognized as promising chassis for photosynthetic production of commodity chemicals with low environmental impact .

• Developing stress-resistant strains: Understanding how EF-Ts interacts with EF-Tu in response to oxidative stress could inform the development of cyanobacterial strains with enhanced photosynthetic efficiency under challenging environmental conditions .

• Biosensors for oxidative stress: The sensitivity of the EF-Ts/EF-Tu system to reactive oxygen species makes it a potential candidate for developing biosensors that detect oxidative stress in environmental or industrial settings .

• Markerless strain engineering: Advanced genetic tools like the mutated pheS counter-selection system enable precise, repeated modifications of cyanobacterial genomes without antibiotic markers, which is crucial for biotechnology applications requiring multiple genetic changes .

• Photosynthetic bioproduction: Enhanced understanding of translation factors in photosynthetic organisms contributes to optimizing these organisms for sustainable production of biofuels and high-value compounds.

• Synthetic biology applications: EF-Ts could be engineered to optimize translation in synthetic genetic circuits designed for specific biotechnological outputs in photosynthetic organisms.

To implement these applications, researchers can leverage markerless genetic modification techniques that allow for precise engineering of tsf and related genes, enabling the development of highly specialized strains for various biotechnology purposes .

What are the current knowledge gaps in understanding Elongation Factor Ts in Synechococcus sp.?

Despite significant advances in understanding elongation factors in cyanobacteria, several knowledge gaps remain regarding Elongation Factor Ts in Synechococcus sp.:

• The precise mechanism by which EF-Ts responds to oxidative stress conditions and how this affects its interaction with EF-Tu requires further investigation.

• The structural details of how EF-Ts facilitates the conformational changes in EF-Tu that expose ROS-sensitive residues like C82 have not been fully elucidated .

• The regulation of tsf gene expression under varying environmental conditions and its correlation with photosynthetic efficiency remains to be thoroughly characterized.

• The potential role of EF-Ts in stress response pathways beyond its canonical function in translation elongation merits further exploration.

• The development of optimized genetic manipulation techniques specifically tailored for studying EF-Ts function in various Synechococcus strains would address current technical limitations .