The ytfL protein is classified as an UPF0053 inner membrane protein found in Escherichia coli. It is a full-length protein consisting of 447 amino acids (1-447aa) . The protein is known to be associated with the inner membrane of E. coli, suggesting it plays a role in membrane-related functions or processes. The official UniProt ID for this protein is P0AE45, which provides a standardized reference for researchers studying this protein .
The ytfL protein is also known by several synonyms including paeA, b4218, JW4177, and "Polyamine export protein," which suggests potential functional roles in polyamine transport across the bacterial membrane . This diversity in nomenclature reflects the ongoing characterization of this protein and its multiple potential functions within bacterial cells.
The complete amino acid sequence of ytfL has been determined and is provided in product specifications from commercial sources. The sequence is as follows:
MLNSILVILCLIAVSAFFSMSEISLAASRKIKLKLLADEGNINAQRVLNMQENPGMFFTV VQIGLNAVAILGGIVGDAAFSPAFHSLFSRYMSAELSEQLSFILSFSLVTGMFILFADLT PKRIGMIAPEAVALRIINPMRFCLYVCTPLVWFFNGLANIIFRIFKLPMVRKDDITSDDI YAVVEAGALAGVLRKQEHELIENVFELESRTVPSSMTPRENVIWFDLHEDEQSLKNKVAE HPHSKFLVCNEDIDHIIGYVDSKDLLNRVLANQSLALNSGVQIRNTLIVPDTLTLSEALE SFKTAGEDFAVIMNEYALVVGIITLNDVMTTLMGDLVGQGLEEQIVARDENSWLIDGGTP IDDVMRVLDIDEFPQSGNYETIGGFMMFMLRKIPKRTDSVKFAGYKFEVVDIDNYRIDQL LVTRIDSKATALSPKLPDAKDKEESVA
Analysis of this sequence reveals several hydrophobic regions consistent with a membrane-embedded protein. The presence of these hydrophobic domains supports its classification as an inner membrane protein, likely containing multiple transmembrane segments that anchor it within the bacterial cell membrane.
The gene encoding ytfL is located in the E. coli genome and has been thoroughly characterized. Gene information available from commercial suppliers indicates that the ytfL gene (also designated as b4218 or JW4177) encodes this inner membrane protein . The synonym "paeA" (polyamine export protein A) suggests a potential role in polyamine transport or regulation, which may be significant for bacterial stress responses and survival under various environmental conditions.
Recombinant ytfL protein is typically produced using E. coli expression systems, which provide an efficient and cost-effective method for generating significant quantities of the protein for research purposes . The use of E. coli as both the source organism and expression host offers advantages in terms of protein folding and post-translational modifications that might be essential for proper function.
According to product information, the recombinant ytfL protein is commonly expressed with an N-terminal His-tag, which facilitates purification and detection without significantly altering the protein's structure or function . This expression strategy has proven effective for producing full-length ytfL protein (1-447 amino acids) that retains its structural integrity.
Multiple commercial sources offer the recombinant ytfL protein with consistent specifications, indicating the reliability of current expression methods. These include catalog numbers RFL21376EF, RFL21409EF, and RFL32308EF, all specifying the full-length protein with His-tag expressed in E. coli .
The purification of recombinant ytfL typically leverages the affinity tag (commonly His-tag) added during the expression process. The His-tagged ytfL protein can be efficiently purified using standard affinity chromatography techniques, resulting in preparations with greater than 90% purity as determined by SDS-PAGE analysis .
Following purification, the protein is generally provided in a lyophilized powder form, which enhances stability during shipping and storage . The final product typically contains the full-length ytfL protein with high purity suitable for various research applications including structural studies, functional assays, and antibody production.
Commercial suppliers of recombinant ytfL implement several quality control measures to ensure product consistency and reliability. These include:
Purity assessment via SDS-PAGE, with specifications typically indicating greater than 90% purity .
Verification of protein identity through techniques such as mass spectrometry or Western blotting.
Functional testing where applicable, though specific activity assays for ytfL are not detailed in the available information.
Proper storage and handling recommendations are provided to maintain protein stability and activity. These include storing the lyophilized powder at -20°C to -80°C, with aliquoting recommended for multiple use to avoid repeated freeze-thaw cycles . Reconstitution guidelines specify using deionized sterile water to achieve concentrations of 0.1-1.0 mg/mL, with the addition of 5-50% glycerol (typically 50% final concentration) for long-term storage .
The ytfL protein is classified as an inner membrane protein, consistent with its amino acid sequence containing multiple hydrophobic regions that likely form transmembrane domains . This membrane localization suggests ytfL plays a role in processes occurring at or across the bacterial inner membrane, potentially including transport, signaling, or structural functions.
The UPF0053 classification indicates that ytfL belongs to a family of uncharacterized protein families (UPF), specifically the 0053 group. Proteins in this category typically have conserved sequences and structural features, but their precise functions may not be fully elucidated .
Based on its nomenclature and synonyms, ytfL (also known as paeA or "Polyamine export protein") may be involved in polyamine transport processes in E. coli . Polyamines are essential molecules for cellular growth and development in many organisms, including bacteria, and their transport across membranes is crucial for maintaining cellular homeostasis.
While the specific molecular function of ytfL remains to be fully characterized, its classification as a membrane protein and potential involvement in polyamine export suggests it may play roles in:
Regulating intracellular polyamine concentrations
Facilitating the export of excess polyamines
Contributing to bacterial stress responses
Maintaining membrane integrity under varying environmental conditions
It's worth noting that while ytfL appears to be primarily studied in E. coli, similar proteins might exist in other bacterial species with potentially conserved functions. Comparative genomic and proteomic analyses could reveal evolutionary relationships and functional conservation across different bacterial species.
Recombinant ytfL protein is commercially available for various research applications, indicating ongoing scientific interest in this protein . Current applications may include:
Structural studies to determine the three-dimensional conformation of ytfL
Functional assays to investigate potential transport activities
Generation of antibodies against ytfL for detection and localization studies
Protein-protein interaction studies to identify binding partners
The availability of high-purity recombinant ytfL from commercial sources facilitates these research endeavors by providing consistent and reliable material for experimentation .
While specific biotechnological applications of ytfL are not directly mentioned in the search results, membrane proteins with transport functions often have potential applications in:
Development of biosensors for detecting specific molecules
Engineering of bacterial strains with enhanced production or export capabilities
Design of drug delivery systems leveraging membrane transport mechanisms
Creation of bioremediation tools for environmental applications
If ytfL indeed functions in polyamine transport, it might be leveraged in biotechnological applications requiring controlled polyamine concentrations or transport across membranes.
Based on the available information, several promising research directions for ytfL could include:
Detailed structural characterization using techniques such as X-ray crystallography or cryo-electron microscopy
Functional studies to definitively establish its role in polyamine transport
Investigation of potential regulatory mechanisms controlling ytfL expression and activity
Exploration of its interaction network within the bacterial membrane
Assessment of its importance in bacterial stress responses and environmental adaptation
These investigations would contribute to a more comprehensive understanding of ytfL's biological significance and potential applications.
KEGG: ecj:JW4177
STRING: 316385.ECDH10B_4413
Recombinant Escherichia coli UPF0053 inner membrane protein ytfL is a full-length protein consisting of 447 amino acids (residues 1-447). The recombinant version is typically expressed with a histidine tag to facilitate purification and downstream applications. This protein is derived from E. coli and is categorized as an inner membrane protein .
The protein is available in multiple catalog formats with consistent structural characteristics as shown in the following table:
| Catalog Number | Product Name | Source | Species | Tag | Protein Length |
|---|---|---|---|---|---|
| RFL21376EF | Recombinant Full Length Upf0053 Inner Membrane Protein Ytfl(Ytfl) Protein, His-Tagged | E.coli | E.coli | His | Full Length (1-447) |
| RFL21409EF | Recombinant Full Length Escherichia Coli Upf0053 Inner Membrane Protein Ytfl(Ytfl) Protein, His-Tagged | E.coli | E.coli | His | Full Length (1-447) |
| RFL32308EF | Recombinant Full Length Upf0053 Inner Membrane Protein Ytfl(Ytfl) Protein, His-Tagged | E.coli | E.coli | His | Full Length (1-447) |
When designing experiments to study ytfL protein function, implement a structured experimental research design focusing on clearly defined variables. Start by establishing a testable hypothesis about ytfL's function in E. coli. For example, you might hypothesize that "ytfL impacts membrane integrity under specific stress conditions."
Your methodology should include:
Define your independent variable (e.g., presence/absence of ytfL protein) and dependent variables (e.g., membrane integrity measurements, cellular growth rates) .
Establish control groups (wild-type E. coli) and experimental groups (ytfL knockout or overexpression strains) .
Ensure random sampling to eliminate selection bias in your bacterial populations .
Implement quantitative measurements that generate reliable, reproducible data4.
Design appropriate statistical analyses to determine significance of observed differences between control and experimental groups .
For membrane proteins like ytfL, consider complementary approaches such as protein localization studies, interaction assays, and phenotypic analyses under various growth conditions.
Studying ytfL protein interactions in complex membrane environments requires sophisticated methodological approaches that preserve native membrane context while enabling sensitive detection of interacting partners. The following multi-layered methodology is recommended:
First, implement a combination of genetic and biochemical approaches. Begin with in vivo crosslinking studies using membrane-permeable crosslinkers to capture transient interactions within the native membrane environment. Follow with co-immunoprecipitation using His-tag antibodies to isolate the ytfL-containing complexes .
For mapping the interaction interface, employ hydrogen-deuterium exchange mass spectrometry (HDX-MS) or site-directed mutagenesis coupled with functional assays. To validate direct interactions, reconstitute purified ytfL into liposomes or nanodiscs with putative interaction partners and assess binding through microscale thermophoresis or surface plasmon resonance.
For comprehensive interactome analysis, implement proximity-based labeling methods such as BioID or APEX2 fused to ytfL to identify proximal proteins in living cells. Analyze the resulting data using computational approaches to distinguish direct interactions from indirect associations within the membrane proteome.
When confronting apparently contradictory findings regarding ytfL function or characteristics in the literature, implement a structured analytical framework:
Classify the type of contradiction according to Sarafraz's framework: determine whether it represents a logical contradiction in biology, a contradiction in literature reporting, or a contradiction in extracted data due to incomplete context .
Systematically evaluate key experimental parameters across studies showing contradictory results:
Strain backgrounds and genetic modifications
Expression systems and tags used
Environmental conditions and growth media
Detection methods and their sensitivity thresholds
Temporal aspects of measurements
Examine whether contradictions arise from underspecified contexts, such as:
Implement verification experiments that directly test competing claims under identical conditions, ensuring:
This systematic approach allows researchers to determine whether contradictions represent genuine biological complexity, methodological differences, or reporting inconsistencies.
When designing experiments with recombinant ytfL, controlling several critical variables is essential for generating reliable and reproducible results:
Expression System Variables:
Induction conditions (inducer concentration, temperature, duration)
Host strain characteristics (protease deficiency, rare codon supplementation)
Vector design (promoter strength, tag position, linker composition)
Purification Variables:
Storage and Stability Variables:
Temperature conditions
Buffer composition for long-term stability
Freeze-thaw cycle effects
Protein concentration effects on aggregation
Experimental Condition Variables:
Temperature and pH during assays
Presence of cofactors or binding partners
Time-dependent changes in activity
Surface adsorption effects
Control these variables by implementing standardized protocols with detailed documentation of all conditions, including lot-to-lot variation in reagents. Validate protein quality through multiple analytical methods (SDS-PAGE, size exclusion chromatography, activity assays) before proceeding to functional studies. Include appropriate positive and negative controls in all experiments, and consider the use of internal standards for quantitative measurements .
Designing experiments to distinguish between direct and indirect effects of ytfL on cellular processes requires a multi-faceted approach combining genetics, biochemistry, and systems biology:
Implement genetic approaches with temporal control:
Utilize inducible expression systems for precise temporal control of ytfL expression
Employ rapid degradation systems (e.g., auxin-inducible degrons) to quickly remove ytfL protein
Monitor immediate versus delayed effects following ytfL manipulation
Develop direct biochemical assays:
Establish in vitro reconstitution systems with purified components
Design assays that measure specific biochemical activities potentially affected by ytfL
Implement structure-function studies using targeted mutations to identify critical functional domains
Apply systems biology approaches:
Conduct time-resolved transcriptomics and proteomics following ytfL perturbation
Use network analysis to distinguish primary response nodes from secondary effects
Implement mathematical modeling to predict direct versus indirect effects
Consider the experimental design features:
This methodology requires carefully distinguishing between the independent variable (ytfL manipulation) and dependent variables (cellular processes) , while controlling for other factors that might influence the observed outcomes.
When analyzing complex datasets from ytfL protein studies, selecting appropriate statistical approaches depends on experimental design, data types, and research questions. A comprehensive statistical framework should include:
Exploratory Data Analysis:
Begin with visualization techniques (histograms, box plots, scatter plots) to identify data patterns and potential outliers
Assess data normality using Shapiro-Wilk or Kolmogorov-Smirnov tests
Examine data distributions and consider transformations if necessary
Hypothesis Testing Framework:
For comparing experimental groups (e.g., wild-type vs. ytfL mutant):
For time-series data (e.g., protein activity over time):
Consider repeated measures ANOVA or mixed-effects models
Apply time-series analysis methods for temporal patterns
Multivariate Analysis for Complex Relationships:
Principal Component Analysis (PCA) to identify major sources of variation
Cluster analysis to identify patterns in multi-dimensional data
Partial Least Squares Discriminant Analysis (PLS-DA) for identifying discriminating variables
Model Building and Validation:
Develop predictive models using regression techniques
Implement cross-validation strategies to assess model robustness
Consider Bayesian approaches for incorporating prior knowledge
When analyzing experimental results, ensure statistical power through appropriate sample sizes and account for multiple testing corrections when performing numerous comparisons. Document all data processing steps and analysis decisions to ensure reproducibility4.
Integrating structural data with functional analysis of ytfL requires a methodical approach that bridges atomic-level insights with biological function:
Structure-Function Correlation Methodology:
Map conservation patterns onto structural models to identify functionally important regions
Analyze electrostatic surface properties to predict interaction interfaces
Identify potential binding pockets or catalytic sites
Design targeted mutations based on structural features for functional validation
Dynamics-Based Analysis:
Implement molecular dynamics simulations to understand protein flexibility
Identify conformational changes that might be associated with function
Analyze potential allosteric communication pathways within the protein structure
Integration of Experimental Approaches:
Combine structural data (X-ray crystallography, cryo-EM, NMR) with biochemical assays
Correlate structural features with in vivo phenotypes using site-directed mutagenesis
Use crosslinking or footprinting methods to validate predicted interaction sites
Data Integration Framework:
Develop computational pipelines that integrate multiple data types
Implement machine learning approaches to identify patterns across datasets
Create visualization tools that allow simultaneous analysis of structural and functional data
This integrated approach should follow experimental research design principles, clearly defining the relationships between structural features (independent variables) and functional outcomes (dependent variables) , while maintaining rigorous statistical analysis of correlations between structure and function.
When confronting contradictory reports about ytfL function, implement a systematic methodology based on scientific evidence evaluation principles:
Comprehensive Literature Assessment:
Catalog all published findings on ytfL function using systematic review methodology
Classify contradictions using Sarafraz's framework (logical contradiction in biology, contradiction in literature, or contradiction in extracted data due to incomplete context)
Create a structured comparison matrix of experimental conditions across studies
Critical Variable Identification:
Analyze methodological differences between contradictory studies:
Expression systems and purification methods
Experimental conditions (pH, temperature, buffer composition)
Measurement techniques and their limitations
Strain backgrounds and genetic modifications
Hypothesis Generation for Contradiction Resolution:
Formulate testable hypotheses that could explain the observed contradictions
Consider context-dependent function, post-translational modifications, or strain-specific effects
Design experiments specifically targeting the source of contradiction
Standardized Verification Experiments:
This systematic approach helps distinguish genuine biological complexity from methodological artifacts, advancing the field's understanding of ytfL function while maintaining scientific rigor.
Optimizing high-throughput screening methodologies for ytfL membrane protein interactions requires specialized approaches that address the challenges of membrane protein biology:
Screening Platform Development:
Adapt yeast two-hybrid systems for membrane proteins (split-ubiquitin or MYTH systems)
Implement bimolecular fluorescence complementation (BiFC) in bacterial expression systems
Develop protein fragment complementation assays compatible with membrane environments
Optimize surface display technologies for presenting ytfL in proper orientation
Sample Preparation Optimization:
Standardize expression conditions to ensure consistent protein quality
Develop gentle solubilization protocols that maintain native interaction interfaces
Implement quality control metrics to verify proper folding and membrane integration
Consider nanodiscs or liposome reconstitution for maintaining native-like environment
Assay Development Strategy:
Design primary screens with high sensitivity even at the cost of specificity
Implement orthogonal secondary screens to eliminate false positives
Include appropriate positive and negative controls on each screening plate
Develop quantitative readouts rather than binary outcomes
Data Analysis Framework:
Implement statistical methods appropriate for high-throughput data
Develop normalization procedures to account for plate-to-plate variation
Apply machine learning algorithms to identify patterns in complex datasets
Create visualization tools for intuitive data interpretation
This methodology should follow experimental research design principles with clearly defined variables, appropriate controls, and robust statistical analysis , while adapting these principles to the specific challenges of membrane protein biology.