Recombinant Yersinia pestis bv. Antiqua UPF0299 membrane protein YPN_2465 (YPN_2465)

How does YPN_2465 relate to other Yersinia pestis membrane proteins?

YPN_2465 belongs to the UPF0299 family of membrane proteins. While not explicitly described in the search results as an Ail homolog, it may share functional similarities with other Y. pestis membrane proteins. The Ail (Attachment invasion locus) protein in Y. pestis, for instance, is known to have multiple homologs (y1324, y1682, y2446, and y2034) .
Sequence alignment and phylogenetic analysis would be appropriate methods to determine the evolutionary relationship between YPN_2465 and other membrane proteins in Yersinia species. Such analyses typically involve:

• Multiple sequence alignment using tools like ClustalW or MUSCLE

• Construction of phylogenetic trees using maximum likelihood or Bayesian methods

• Analysis of conserved domains and motifs that might indicate functional similarities

What are the optimal conditions for expressing recombinant YPN_2465?

For optimal expression of recombinant YPN_2465, researchers should consider the following methodological approach:

• Expression System: E. coli is commonly used for expression of recombinant Yersinia proteins, as indicated in the product information .

• Vector Selection: Vectors containing appropriate promoters (T7, tac) and fusion tags (His-tag) are recommended for purification purposes.

• Induction Conditions: Optimize IPTG concentration (typically 0.1-1.0 mM), temperature (often lowered to 16-25°C for membrane proteins), and induction time (4-16 hours).

• Extraction Protocol: As YPN_2465 is a membrane protein, detergent-based extraction methods should be employed after cell lysis. Common detergents include n-dodecyl-β-D-maltoside (DDM), n-octyl-β-D-glucopyranoside (OG), or CHAPS.

• Purification Strategy: For His-tagged proteins, immobilized metal affinity chromatography (IMAC) followed by size exclusion chromatography is recommended to achieve high purity.

• Storage: The purified protein should be stored in Tris-based buffer with 50% glycerol at -20°C for short-term storage or -80°C for long-term preservation, as recommended for the commercially available product .

What experimental design considerations are essential when studying membrane proteins like YPN_2465?

When designing experiments for studying membrane proteins like YPN_2465, researchers should follow these systematic steps:

• Define clear variables:

  • Independent variables might include expression conditions, purification methods, or experimental treatments

  • Dependent variables could include protein yield, activity, or structural integrity

  • Control for extraneous variables such as temperature fluctuations or batch effects

• Formulate specific hypotheses regarding protein function or structure based on bioinformatic predictions and homology to related proteins.

• Design appropriate treatments that manipulate the independent variables in a controlled manner.

• Consider between-subjects or within-subjects experimental designs depending on your research question.

• Establish reliable measurement methods for your dependent variables .
  For membrane proteins specifically, additional considerations include:

• Detergent selection based on protein stability and downstream applications

• Lipid composition for reconstitution experiments

• Proper controls for detergent effects on assays

• Validation of proper protein folding and orientation after purification

What methods are recommended for studying YPN_2465's role in bacterial pathogenesis?

To investigate YPN_2465's potential role in bacterial pathogenesis, researchers should consider a multi-faceted approach:

• Gene Deletion Studies:

  • Create knockout mutants using homologous recombination or CRISPR-Cas9

  • Compare virulence phenotypes between wild-type and mutant strains in appropriate infection models

  • Complement the mutation to confirm specificity of observed phenotypes

• Cell Culture Assays:

  • Adhesion and invasion assays using relevant human cell lines

  • Cytotoxicity assays to assess potential role in host cell damage

  • Immunofluorescence microscopy to track protein localization during infection

• Serum Resistance Testing:

  • If YPN_2465 functions similarly to Ail, evaluate bacterial survival in normal human serum

  • Compare complement deposition on wild-type versus mutant bacteria

• Host Response Assessment:

  • Measure cytokine production in infected cells or tissues

  • Assess recruitment of immune cells in infection models

  • Evaluate impact on inflammatory signaling pathways

• Interaction Studies:

  • Identify potential host binding partners using pull-down assays

  • Verify interactions using techniques such as surface plasmon resonance (SPR)

  • Investigate binding to extracellular matrix components like laminin or fibronectin

How can researchers determine if YPN_2465 interacts with host extracellular matrix components?

To investigate potential interactions between YPN_2465 and host extracellular matrix (ECM) components, researchers should implement the following methodological approach:

• Protein-Protein Interaction Assays:

  • ELISA-based binding assays with purified ECM components (laminin, fibronectin, collagen)

  • Surface plasmon resonance (SPR) to determine binding kinetics and affinities

  • Far-Western blotting with ECM proteins

• Cell-Based Adhesion Assays:

  • Express YPN_2465 in a non-adherent bacterial strain

  • Assess adhesion to ECM-coated surfaces

  • Perform competitive inhibition with antibodies against specific ECM components

• Mutagenesis Studies:

  • Create targeted mutations in predicted binding domains

  • Evaluate impact on binding phenotypes

  • For example, if YPN_2465 functions like Ail, mutations in extracellular loops might disrupt ECM interactions

• Structural Analysis:

  • X-ray crystallography or cryo-EM to identify binding sites

  • Molecular docking simulations with ECM proteins

  • Similar to studies with Ail that identified heparin-binding sites

• In vivo Validation:

  • Use animal models to confirm the biological relevance of identified interactions

  • Evaluate how disrupting these interactions affects colonization or dissemination

How does YPN_2465 compare structurally and functionally across different Yersinia pestis strains?

Analysis of YPN_2465 across different Y. pestis strains reveals important structural and functional insights:

• Sequence Variation Analysis:
  While specific information about YPN_2465 variation is limited in the search results, we can draw parallels from studies of Ail proteins in Y. pestis. Variability in membrane proteins often occurs at key functional sites. For example, Ail shows variability at position 126 (Val/Phe) and position 137 (presence/absence of Ser) across different Y. pestis strains .

• Comparative Methodology:

  • Collect YPN_2465 sequences from multiple Y. pestis strains

  • Perform multiple sequence alignments to identify variable regions

  • Map variations onto predicted structural models

  • Correlate variations with differences in virulence or host range

• Evolutionary Analysis:

  • Calculate selection pressures (dN/dS ratios) at variable sites

  • Perform ancestral state reconstruction to understand evolutionary trajectory

  • Correlate genetic changes with ecological or host shifts

• Functional Impact Testing:

  • Express variants from different strains

  • Compare biochemical properties and binding affinities

  • Assess impact on bacterial adhesion, invasion, and immune evasion

What role might YPN_2465 play in the adaptation of Yersinia pestis to different mammalian hosts?

Understanding YPN_2465's potential role in host adaptation requires consideration of Y. pestis' complex lifecycle involving different mammalian hosts and flea vectors:

• Host Range Analysis:

  • Compare YPN_2465 sequences from strains isolated from different hosts

  • Identify potential adaptive mutations associated with specific host ranges

  • Evaluate binding to serum components from different host species

• Experimental Approach:

  • Express YPN_2465 variants in heterologous systems

  • Test interaction with cells and tissues from different host species

  • Assess contributions to bacterial survival in different host environments

• Evolutionary Context:

  • Y. pestis maintains stable foci in diverse environments across the Americas, Africa, and Eurasia

  • Adaptation to both burrowing and non-burrowing mammals with varying susceptibility to plague is crucial for persistence

  • Membrane proteins often serve as key mediators of host-pathogen interactions and may be subject to positive selection during host switches

• Transmission Cycle Considerations:

  • Evaluate potential roles in flea-mammal transmission

  • Assess contribution to persistence in soil environments between host infections

  • Investigate involvement in different plague presentations (bubonic, septicemic)

How might structural studies of YPN_2465 inform therapeutic development against Yersinia pestis?

Advanced structural studies of YPN_2465 could provide valuable insights for therapeutic development through the following approaches:

• Structural Determination Methods:

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

  • Cryo-electron microscopy to visualize protein in native-like environments

  • NMR studies of specific domains or peptide fragments

  • Molecular dynamics simulations to understand conformational flexibility

• Structure-Based Drug Design:

  • Identification of druggable pockets or interaction interfaces

  • Virtual screening of compound libraries against identified sites

  • Fragment-based drug discovery approaches

  • Peptide inhibitor design targeting key functional regions

• Epitope Mapping for Immunotherapy:

  • Identification of surface-exposed, conserved epitopes

  • Assessment of accessibility during infection

  • Evaluation of protective potential through passive immunization studies

• Translational Considerations:

  • If YPN_2465 functions similarly to Ail in mediating host-cell interactions and complement resistance, targeting this protein could potentially reduce virulence or enhance clearance by host defenses

  • Understanding structural determinants of species-specificity could help design therapeutics with reduced off-target effects

What are the methodological challenges in determining the membrane topology of YPN_2465 and how can they be addressed?

Determining membrane protein topology presents significant technical challenges that require specialized approaches:

• Computational Prediction Methods:

  • Transmembrane helix prediction algorithms (TMHMM, HMMTOP)

  • Topology prediction based on positive-inside rule

  • Hydrophobicity analysis and conservation mapping

  • Integration of evolutionary information through multiple sequence alignments

• Experimental Verification Approaches:

  • Cysteine scanning mutagenesis with selective labeling of exposed residues

  • Protease protection assays to identify domains accessible from different sides of the membrane

  • Fusion reporter systems (PhoA/LacZ) to determine cytoplasmic vs. periplasmic orientation

  • Site-directed fluorescence labeling combined with quenching assays

• Structural Biology Techniques:

  • Cryo-EM of membrane-embedded protein

  • X-ray crystallography with appropriate detergent/lipid environments

  • Solid-state NMR to determine orientation within membranes

  • EPR spectroscopy with site-directed spin labeling

• Integration of Methods:

  • Combining computational predictions with targeted experimental validation

  • Iterative refinement of structural models based on experimental constraints

  • Cross-validation using complementary approaches

• Challenges Specific to YPN_2465:

  • As a relatively small membrane protein (135 amino acids), distinguishing transmembrane segments from membrane-associated domains can be difficult

  • Expression and purification in native conformation requires careful optimization

  • Potential for oligomerization may complicate interpretation of results