Recombinant Salmonella paratyphi C UPF0283 membrane protein ycjF (ycjF)

What expression systems are recommended for recombinant ycjF protein production?

E. coli is the predominant expression system for recombinant ycjF protein production. Based on available data, recombinant Salmonella paratyphi A UPF0283 membrane protein ycjF was successfully expressed in E. coli with an N-terminal His tag . The same approach is applicable for S. paratyphi C ycjF due to the high sequence similarity between these proteins.

When designing an expression protocol, researchers should consider:

• Vector selection: Vectors containing strong inducible promoters (T7, tac) are suitable for membrane protein expression

• Fusion tags: N-terminal His-tag facilitates purification while minimizing interference with membrane insertion

• Growth conditions: Lower temperatures (16-25°C) after induction may increase properly folded protein yield

• Induction parameters: IPTG concentration and induction timing affect expression levels

Membrane proteins present particular challenges for recombinant expression. For ycjF specifically, the transmembrane regions may require optimization of detergent conditions during purification to maintain native structure.

What are the optimal storage conditions for preserving recombinant ycjF protein activity?

For optimal preservation of recombinant ycjF protein activity, the following storage conditions are recommended:

• Long-term storage: Store at -20°C/-80°C upon receipt, with aliquoting necessary for multiple use .

• Storage buffer: Tris/PBS-based buffer with 6% Trehalose, pH 8.0 . The trehalose acts as a cryoprotectant.

• Reconstitution: Reconstitute protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL .

• Working aliquots: For short-term use, store working aliquots at 4°C for up to one week .

• Freeze-thaw cycles: Repeated freezing and thawing is not recommended .

• Glycerol addition: Addition of 5-50% glycerol (final concentration) is recommended when aliquoting for long-term storage .

How can researchers verify the purity and integrity of recombinant ycjF protein preparations?

To verify the purity and integrity of recombinant ycjF protein preparations, researchers should employ multiple complementary analytical techniques:

• SDS-PAGE analysis: Should show >90% purity with a band corresponding to the expected molecular weight of the full-length protein (approximately 38-40 kDa for the 353 amino acid sequence plus His-tag) .

• Western blotting: Using anti-His antibodies to confirm the presence of the His-tagged protein and anti-ycjF antibodies (if available) to verify protein identity.

• Mass spectrometry:

  • MALDI-TOF or ESI-MS for molecular weight confirmation

  • Peptide mass fingerprinting after tryptic digestion to verify sequence coverage

  • Native mass spectrometry to assess oligomeric state in solution

• Size exclusion chromatography: To evaluate protein homogeneity and detect any aggregation.

• Circular dichroism: To assess secondary structure and proper folding of the membrane protein.

For membrane proteins like ycjF, researchers should be particularly vigilant about detergent effects on protein structure and function. Proper characterization should include assessment of the protein in detergent micelles or reconstituted into lipid bilayers/nanodiscs to more closely approximate native conditions.

What methodologies are recommended for studying ycjF protein interactions with other bacterial or host proteins?

For studying ycjF protein interactions, several methodologies are particularly effective for membrane proteins:

• Native-nanoBleach analysis: This technique has been successfully applied to membrane proteins to study oligomeric distribution in native nanodiscs . The approach allows for analysis of membrane proteins in a near-native environment and can reveal monomeric, dimeric, and higher-order oligomeric states.

• Pull-down assays and co-immunoprecipitation: Using His-tagged ycjF as bait, researchers can identify interaction partners from bacterial lysates or host cell extracts. Care must be taken to use appropriate detergents that preserve protein-protein interactions while solubilizing membrane complexes.

• Bacterial two-hybrid systems: Modified for membrane proteins, these systems can be used to screen for potential interaction partners.

• Cross-linking mass spectrometry (XL-MS): Chemical cross-linking followed by mass spectrometry analysis can identify proteins in close proximity to ycjF in vivo.

• Fluorescence techniques:

  • FRET (Förster Resonance Energy Transfer) for studying protein-protein interactions in live cells

  • Fluorescence correlation spectroscopy (FCS) for dynamics and interactions

  • Single-molecule tracking to monitor ycjF behavior in membranes

• Surface plasmon resonance (SPR): For quantitative measurement of binding kinetics between purified ycjF and candidate interacting proteins.

When investigating ycjF interactions, researchers should consider its potential role in Salmonella pathogenesis. Given that S. paratyphi C causes typhoid fever, examining interactions between ycjF and host proteins involved in immune responses or cellular invasion pathways would be particularly valuable.

How can researchers distinguish the functional role of ycjF in S. paratyphi C from its homologs in other Salmonella strains?

To distinguish the functional role of ycjF in S. paratyphi C from its homologs in other Salmonella strains, researchers should employ a multi-faceted comparative approach:

• Comparative genomic analysis:

  • Analyze sequence conservation of ycjF across typhoid-causing and non-typhoid Salmonella strains

  • Compare genetic context (surrounding genes) of ycjF in different Salmonella genomes

  • Identify strain-specific single nucleotide polymorphisms or amino acid substitutions that might influence function

• Gene knockout and complementation experiments:

  • Generate ycjF deletion mutants in multiple Salmonella strains

  • Compare phenotypes (growth rates, stress responses, virulence) across strains

  • Perform cross-complementation experiments (e.g., expressing S. paratyphi C ycjF in S. typhimurium ycjF knockout)

• Host-pathogen interaction studies:

  • Compare invasion and survival rates of wild-type and ΔycjF strains in human cell lines

  • Assess differential responses in host immune recognition between strains

  • Evaluate strain-specific contribution to typhoid pathogenesis using appropriate animal models

• Transcriptomic and proteomic comparisons:

  • Compare gene expression profiles between wild-type and ΔycjF mutants across strains

  • Identify strain-specific changes in protein expression using comparative proteomics

This approach would be particularly informative given the evolutionary relationships among Salmonella strains. S. paratyphi C shares more genes with S. choleraesuis (4,346 genes) than with S. typhi (4,008 genes), despite both S. paratyphi C and S. typhi causing typhoid fever in humans . This suggests that these typhoid agents evolved independently through convergent evolution, potentially employing different molecular mechanisms involving proteins like ycjF .

What is known about the potential role of ycjF in Salmonella paratyphi C pathogenesis?

The specific role of ycjF in Salmonella paratyphi C pathogenesis remains incompletely characterized, but several lines of evidence suggest potential involvement in bacterial adaptation to the human host:

• Evolutionary context: Genomic analysis indicates that S. paratyphi C has diverged from a common ancestor with S. choleraesuis (a swine pathogen) "by accumulating genomic novelty during adaptation to man" . The differential selection pressures during this host adaptation likely affected membrane proteins like ycjF that interface with the host environment.

• Conservation patterns: The UPF0283 family membrane proteins appear conserved across pathogenic Salmonella strains, suggesting functional importance, but sequence variations might contribute to host specificity and pathogenic mechanisms.

• Membrane localization: As a membrane protein, ycjF is positioned at the bacteria-host interface, where it could potentially:

  • Contribute to adhesion or invasion processes

  • Participate in nutrient acquisition in the host environment

  • Play a role in evading host immune responses

  • Function in signaling pathways that regulate virulence gene expression

• Typhoid-specific adaptations: S. paratyphi C causes systemic typhoid fever rather than self-limited gastroenteritis, suggesting adaptations for systemic spread and persistence. The genome shows evidence of "enormous selection pressures during its adaptation to man" , which may have affected ycjF function.

Although no direct experimental evidence links ycjF to specific virulence mechanisms in S. paratyphi C, comparative analysis with S. choleraesuis could reveal adaptations in membrane proteins that facilitate human infection. The fact that S. paratyphi C has shown "greater dN than dS substitutions" compared to S. choleraesuis indicates positive selection for amino acid changes , which could affect proteins like ycjF during host adaptation.

What analytical techniques are most suitable for characterizing the membrane topology and structure of ycjF?

Characterizing the membrane topology and structure of ycjF requires specialized techniques suitable for membrane proteins:

• Computational prediction and analysis:

  • Hydropathy analysis to predict transmembrane segments

  • Topology prediction algorithms (TMHMM, Phobius, TOPCONS)

  • Structural homology modeling using related proteins with known structures

• Experimental topology mapping:

  • Cysteine scanning mutagenesis with accessibility studies

  • Reporter fusion approaches (PhoA, GFP, LacZ) at different positions

  • Protease protection assays to determine cytoplasmic vs. periplasmic domains

• Structural determination approaches:

  • X-ray crystallography of purified protein (challenging for membrane proteins)

  • Cryo-electron microscopy for 3D structure determination

  • NMR spectroscopy for dynamic structural information

  • Hydrogen-deuterium exchange mass spectrometry (HDX-MS) to probe solvent accessibility

• Native mass spectrometry:

  • Analysis of oligomeric organization in detergent-solubilized preparations

  • Native-nanoBleach analysis in native nanodiscs to assess oligomeric distribution

• Advanced microscopy techniques:

  • Atomic force microscopy to visualize membrane proteins in lipid bilayers

  • Single-particle tracking to study dynamics in membranes

  • Super-resolution microscopy for localization studies

• Biochemical assessments:

  • Cross-linking studies to identify proximity relationships

  • Limited proteolysis to identify domain boundaries and flexible regions

  • Fluorescence spectroscopy with site-specific labels

A comprehensive structural analysis would combine computational predictions with experimental validation, beginning with topology mapping to determine membrane orientation before proceeding to more detailed structural studies.

How can researchers design functional assays to elucidate the physiological role of ycjF in bacterial survival and virulence?

Designing functional assays to elucidate the physiological role of ycjF requires a systematic approach that addresses multiple aspects of bacterial physiology and host interaction:

• Gene expression analysis:

  • Measure ycjF expression under different growth conditions (temperature, pH, nutrient limitation)

  • Determine expression changes during infection of host cells

  • Identify co-regulated genes for functional insights

• Phenotypic characterization of ycjF mutants:

  • Growth curves under various stress conditions (acid, oxidative, osmotic stress)

  • Membrane integrity assays (detergent sensitivity, permeability)

  • Antibiotic susceptibility profiles

  • Motility and biofilm formation assays

• Host-pathogen interaction assays:

  • Adhesion and invasion assays with human epithelial cells

  • Survival within macrophages

  • Transepithelial migration models

  • Cytokine induction in host cells

• In vivo infection models:

  • Typhoid mouse model comparing wild-type and ΔycjF strains

  • Competitive index assays in mixed infections

  • Organ colonization patterns

  • Immune response characterization

• Biochemical function assessment:

  • Transport assays using bacterial membrane vesicles

  • Enzymatic activity screens

  • Protein-protein interaction identification

  • Lipid interaction studies

• Comparative analysis across strains:

  • Cross-complementation studies between S. paratyphi C and other Salmonella strains

  • Analysis of strain-specific functional differences

  • Assessment of contribution to host specificity

These assays should be designed with appropriate controls, including complementation of mutant strains with functional ycjF to confirm phenotype specificity. Given that S. paratyphi C evolved to cause typhoid fever in humans through convergent evolution (distinct from S. typhi) , the functional role of ycjF might reveal unique adaptations for human pathogenesis.

What are the challenges in producing sufficient quantities of properly folded recombinant ycjF protein, and how can they be addressed?

Producing properly folded recombinant membrane proteins like ycjF presents several challenges that require specific strategies:

• Expression challenges and solutions:

  • Challenge: Toxicity to host cells when overexpressed

  • Solution: Use tightly regulated expression systems, lower induction temperatures (16-20°C), and reduced inducer concentrations

  • Challenge: Protein aggregation and inclusion body formation

  • Solution: Co-expression with chaperones (GroEL/GroES, DnaK/DnaJ), fusion with solubility-enhancing tags (MBP, SUMO), and optimization of cell growth conditions

• Membrane insertion issues:

  • Challenge: Inefficient insertion into host membranes

  • Solution: Target to the membrane using appropriate signal sequences, consider specialized E. coli strains (C41/C43) designed for membrane protein expression, and optimize membrane targeting sequences

• Extraction and purification strategies:

  • Challenge: Maintaining native structure during extraction

  • Solution: Screen multiple detergents (DDM, LMNG, CHAPS) for optimal extraction; consider native nanodiscs for purification

  • Challenge: Low yield during purification

  • Solution: Optimize detergent:protein ratios, include stabilizing additives (glycerol, specific lipids), and use affinity chromatography followed by size exclusion chromatography

• Verifying proper folding:

  • Challenge: Assessing native conformation

  • Solution: Circular dichroism to confirm secondary structure, fluorescence-based thermal stability assays, and functional activity tests if available

• Scale-up considerations:

  • Challenge: Maintaining quality at larger scales

  • Solution: Optimize fermentation parameters (dissolved oxygen, pH control), use fed-batch cultivation, and ensure consistent induction conditions

For ycjF specifically, previous success with His-tagged constructs expressed in E. coli provides a starting point . The final purified protein should achieve >90% purity as determined by SDS-PAGE , with verification of proper folding through multiple biophysical techniques.

How do genomic variations in ycjF across different Salmonella paratyphi strains affect experimental design and interpretation?

Genomic variations in ycjF across different Salmonella paratyphi strains have significant implications for experimental design and data interpretation:

• Sequence variation considerations:

  • Perform multiple sequence alignments of ycjF from different strains to identify conserved and variable regions

  • Design strain-specific primers for gene amplification and cloning

  • Consider strain-specific antibodies for detection if high variation exists

• Experimental design adaptations:

  • Include multiple reference strains in comparative studies

  • Clearly specify the strain origin of ycjF in all experiments

  • Consider complementation with ycjF variants from different strains to assess functional conservation

• Evolutionary context for interpretation:

  • Analyze whether variations reflect neutral mutations or positive selection

  • Consider the evolutionary relationship between strains when interpreting functional differences

  • Remember that S. paratyphi C shows evidence of "enormous selection pressures during its adaptation to man" , which may have affected membrane proteins

• Strain-specific considerations:

  • Recognize that S. paratyphi C is more closely related to S. choleraesuis (sharing 4,346 genes) than to S. typhi (sharing only 4,008 genes)

  • Consider that typhoid-causing strains evolved through convergent evolution rather than from a common ancestor

  • Account for the possibility that ycjF may have different functional roles in different strains

• Data reporting and analysis:

  • Clearly document strain origins in publications

  • Avoid generalizing findings from one strain to all S. paratyphi variants

  • Consider performing phylogenetic analysis to contextualize functional findings

The genomic comparison between S. paratyphi C RKS4594 and other Salmonella strains revealed "differential nucleotide substitutions" between closely related strains , highlighting the importance of strain specificity in experimental design and interpretation.

What are the most reliable reference genes or proteins for normalization when studying ycjF expression levels?

When studying ycjF expression levels in Salmonella paratyphi C, selecting appropriate reference genes for normalization is crucial for reliable quantification. Based on established practices in bacterial gene expression studies:

• Recommended reference genes for normalization:

  • rpoD (sigma factor 70): Demonstrates stable expression across many growth conditions

  • gyrB (DNA gyrase subunit B): Typically maintains consistent expression levels

  • 16S rRNA: Traditionally used, though high abundance may pose technical challenges

  • recA: Shows stability across many environmental conditions in Salmonella species

  • rpoB (RNA polymerase β subunit): Often maintains stable expression

• Validation approach for reference gene selection:

  • Test multiple candidates under experimental conditions of interest

  • Use algorithms like geNorm, NormFinder, or BestKeeper to assess stability

  • Verify stability across different growth phases and stress conditions

  • Consider using geometric means of multiple reference genes for optimal normalization

• Technical considerations:

  • For RT-qPCR studies, design primers with similar amplification efficiencies

  • Ensure reference genes are not co-regulated with ycjF

  • Verify that reference gene expression is not affected by the experimental conditions

  • Consider absolute quantification with standard curves for highly variable conditions

• Special considerations for infection studies:

  • When analyzing expression during host cell infection, verify reference gene stability in intracellular environments

  • Consider dual normalization to both bacterial and host reference genes for mixed samples

  • Use reference genes validated specifically for in vivo or host-cell environments

How might structural analysis of ycjF contribute to understanding bacterial membrane protein evolution in host adaptation?

Structural analysis of ycjF could provide significant insights into bacterial membrane protein evolution during host adaptation:

• Evolutionary structural biology approaches:

  • Comparative structural analysis of ycjF across human-adapted (S. paratyphi C) and animal-adapted (S. choleraesuis) strains

  • Identification of positively selected residues in 3D structural context

  • Mapping of host-specific adaptations onto functionally important domains

• Structural features relevant to host adaptation:

  • Analysis of surface-exposed regions that may interact with host factors

  • Examination of transmembrane domains for adaptation to different host membrane environments

  • Identification of structural motifs that may contribute to immune evasion

• Convergent evolution insights:

  • Comparison of ycjF structures between S. paratyphi C and S. typhi could reveal different structural solutions to similar functional challenges

  • Assessment of whether convergent evolution in typhoid-causing Salmonella strains resulted in similar structural adaptations in membrane proteins

• Methodological approaches:

  • Cryo-EM structures of ycjF from different Salmonella strains

  • Molecular dynamics simulations to assess functional impacts of sequence variations

  • Hydrogen-deuterium exchange mass spectrometry to identify regions with differential dynamics

• Integration with genomic data:

  • Correlation of structural features with genomic evidence of selection

  • Analysis of the relationship between genetic diversity and structural conservation

The genomic comparison of S. paratyphi C with other Salmonella strains revealed "differential nucleotide substitutions" with its closest relative S. choleraesuis , with greater non-synonymous than synonymous substitutions suggesting positive selection during human adaptation. Structural analysis of ycjF could reveal how these substitutions translate to functional adaptations at the protein level.

What are the implications of ycjF research for developing new antimicrobial strategies against typhoid fever?

Research on ycjF could have significant implications for developing novel antimicrobial strategies against typhoid fever:

• Drug target potential assessment:

  • Evaluate essentiality of ycjF for bacterial survival during infection

  • Determine conservation across Salmonella strains to assess breadth of coverage

  • Examine structural uniqueness compared to human proteins to minimize off-target effects

  • Assess accessibility of the protein to small molecule inhibitors

• Structure-based drug design approaches:

  • Identify potential binding pockets in the ycjF structure

  • Perform virtual screening of compound libraries against identified pockets

  • Design inhibitors targeting functionally critical regions

  • Develop peptidomimetics targeting protein-protein interaction surfaces

• Vaccine development considerations:

  • Evaluate immunogenicity of surface-exposed ycjF epitopes

  • Assess protection conferred by anti-ycjF antibodies in animal models

  • Design subunit vaccines incorporating ycjF epitopes

  • Consider ycjF as part of a multi-antigen approach to vaccination

• Anti-virulence strategies:

  • Target ycjF-dependent virulence mechanisms rather than growth

  • Develop compounds that interfere with ycjF-mediated host interactions

  • Design inhibitors that block stress adaptation functions

  • Consider combination approaches targeting multiple membrane proteins

• Diagnostic applications:

  • Develop ycjF-based detection methods for S. paratyphi C

  • Design strain-specific diagnostic tools based on sequence variations

  • Utilize ycjF as a biomarker for antimicrobial resistance monitoring

The genomic analysis of S. paratyphi C indicates that it "does not share a common ancestor with other human-adapted typhoid agents" , suggesting that typhoid pathogenicity evolved independently multiple times. This convergent evolution model underscores the importance of targeting conserved mechanisms required for typhoid pathogenesis, potentially including membrane proteins like ycjF that may have evolved to perform similar functions through different structural adaptations.

How can comparative proteomic approaches enhance our understanding of ycjF function in Salmonella pathogenesis?

Comparative proteomic approaches can significantly enhance understanding of ycjF function in Salmonella pathogenesis through several strategies:

• Differential expression analysis:

  • Compare proteome profiles between wild-type and ΔycjF mutant strains

  • Analyze expression changes under host-mimicking conditions (low pH, low Mg²⁺, antimicrobial peptides)

  • Examine temporal changes in protein expression during infection progression

  • Identify compensatory protein expression in response to ycjF deletion

• Protein-protein interaction networks:

  • Perform immunoprecipitation coupled with mass spectrometry (IP-MS) to identify ycjF interaction partners

  • Use proximity labeling approaches (BioID, APEX) to map the protein neighborhood of ycjF in living bacteria

  • Construct interaction networks specific to infection-relevant conditions

  • Compare interaction networks between S. paratyphi C and related Salmonella strains

• Post-translational modification analysis:

  • Identify modifications on ycjF that may regulate its function (phosphorylation, glycosylation)

  • Examine changes in the bacterial phosphoproteome in response to ycjF deletion

  • Study temporal dynamics of modifications during infection

• Membrane proteome analysis:

  • Compare membrane proteome composition between wild-type and ΔycjF strains

  • Analyze changes in membrane protein complexes using blue native PAGE coupled with MS

  • Examine lipid-protein interactions using lipidomics approaches

  • Study membrane proteome changes during host adaptation

• Functional clusters and pathways:

  • Perform pathway enrichment analysis on differentially expressed proteins

  • Identify functional protein clusters affected by ycjF deletion

  • Correlate proteome changes with virulence phenotypes

• Cross-species comparative proteomics:

  • Compare ycjF-dependent proteome changes between S. paratyphi C and S. choleraesuis

  • Analyze strain-specific protein expression patterns in the context of host adaptation

  • Identify convergent proteomic signatures in typhoid-causing strains

Given that S. paratyphi C has "diverged from a common ancestor with S. choleraesuis by accumulating genomic novelty during adaptation to man" , comparative proteomic approaches between these closely related but functionally distinct strains could reveal how membrane proteins like ycjF contribute to host-specific adaptation and pathogenesis.

What experimental models are most appropriate for studying ycjF function in the context of Salmonella paratyphi C infection?

Selecting appropriate experimental models for studying ycjF function in Salmonella paratyphi C infection requires careful consideration of both in vitro and in vivo approaches:

• Cell culture models:

  • Human intestinal epithelial cells (Caco-2, HT-29): For studying initial attachment and invasion processes

  • Macrophage cell lines (THP-1, U937): For intracellular survival and replication studies

  • 3D organoid cultures: More physiologically relevant intestinal models

  • Co-culture systems: Combining epithelial and immune cells to study complex interactions

• Ex vivo tissue models:

  • Human intestinal explants: Maintains tissue architecture and cell diversity

  • Precision-cut tissue slices: Allows for controlled infection studies with intact tissue structure

  • Perfused organ systems: Models systemic dissemination aspects

• Animal models:

  • Humanized mouse models: Engrafted with human immune cells or tissues

  • Germ-free mice: To study infection without competing microbiota

  • Gallstone mouse model: For studying chronic carriage

  • Non-human primates: For closer physiological relevance to human infection

• Infection conditions to model:

  • Gastrointestinal transit: Acid and bile salt exposure before epithelial contact

  • Intracellular environments: Phagosome acidification, nutrient limitation

  • Systemic spread: Blood, spleen, and liver environments

  • Chronic carriage: Gallbladder conditions

• Specialized approaches:

  • In vivo expression technology (IVET): To identify genes expressed during infection

  • Dual RNA-seq: To simultaneously monitor host and bacterial transcriptomes

  • Intravital microscopy: For real-time imaging of bacteria-host interactions

When selecting models, it's crucial to remember that S. paratyphi C causes typhoid fever, a systemic infection, rather than self-limited gastroenteritis . Therefore, models that allow for studying bacterial dissemination beyond the intestinal epithelium are particularly relevant. Additionally, considering the evolutionary relationship between S. paratyphi C and S. choleraesuis , comparative studies in both human and porcine models could provide insights into host adaptation mechanisms involving ycjF.

How might research on ycjF contribute to broader understanding of bacterial evolution and host adaptation mechanisms?

Research on ycjF can provide valuable insights into broader mechanisms of bacterial evolution and host adaptation:

• Evolutionary models for host specificity:

  • Analysis of ycjF sequence divergence between human-adapted (S. paratyphi C) and animal-adapted (S. choleraesuis) strains

  • Assessment of selection pressures on membrane proteins during host jumps

  • Testing whether ycjF adaptations follow predictable patterns across independently evolved typhoid agents

• Convergent evolution mechanisms:

  • Comparison of ycjF between S. paratyphi C and S. typhi to identify whether independent adaptation to human hosts produced similar functional modifications

  • Assessment of whether "convergent evolution model of the typhoid agents" extends to specific membrane proteins

  • Identification of molecular signatures of convergent functional adaptation

• Functional trade-offs in host adaptation:

  • Examination of whether adaptations in ycjF that enhance fitness in human hosts reduce fitness in other environments

  • Analysis of functional constraints on membrane protein evolution during host specialization

  • Assessment of the relationship between host range and membrane protein conservation

• Genomic plasticity and protein function:

  • Correlation between genomic changes (SNPs, indels, rearrangements) and functional modifications in membrane proteins

  • Analysis of how "enormous selection pressures during adaptation to man" shaped membrane proteome composition

  • Investigation of the role of horizontal gene transfer in membrane protein evolution

• Molecular clock applications:

  • Dating the divergence of ycjF variants across Salmonella strains

  • Correlation with historical patterns of human-pathogen co-evolution

  • Estimation of adaptation rates for membrane proteins during host shifts

• Predictive models for host adaptation:

  • Development of computational approaches to predict membrane protein adaptations during host jumps

  • Identification of signature mutations that facilitate adaptation to new hosts

  • Creation of evolutionary models to forecast potential emerging pathogens

The relationship between S. paratyphi C and S. choleraesuis provides an excellent model for studying bacterial adaptation to different hosts, as they share many genes (4,346) but have diverged through adaptation to different hosts . The fact that S. paratyphi C shows greater non-synonymous than synonymous substitutions compared to S. choleraesuis indicates positive selection during human adaptation , making proteins like ycjF valuable windows into the molecular mechanisms of host adaptation.